I see your situation quite often, and it is one of the most unfortunate situations I come across because you clearly had no say in the circumstances that you find yourself in now. There are several issues and as with all cases, you should consult a lawyer about the issues specific to your case.
First, something you ought to know but that won't make anything easier: as we'll see in a second, for all but a few immigration options you would need to process outside the U.S. But the act of leaving, once a person has accrued "unlawful presence" in the U.S. (this is oversimplified, but "unlawful presence" means time spent here in the U.S. without valid immigration status). 180 days unlawful presence and then leaving the U.S., it';s a three-year bar to coming back, and a ten year bar once a year of unlawful presence stacks up. But you don't start accruing unlawful presence before you turn 18 - and you say you just turned 18. You may not see leaving now as much of an option, but if you leave now before 180 days pass after your 18th birthday and there is some valid way to process you, then you won't be subject to one of these reentry bars.
Most ways to become legal in the U.S. without leaving - and becoming subject to one of the bars once enough time has passed from your 18th birthday - require you to still be in valid immigration status. There may be a few exceptions, depending on your situation.
How were you brought in as a baby? I know - hard to answer. But if you entered illegally ("without inspection"), then there are even fewer options than if you entered with a visa which later expired. If you were brought in legally (you were "inspected" by an immigration officer and can prove it with the I-94 card issued on entry, then getting married to a U.S. citizen here lets you apply for a green card in the U.S. without leaving. I'm not saying to get married just for immigration purposes - this is only legitimate (not to mention possible and sane) if you were planning to marry someone anyway who happened to be a citizen.
Has anyone ever filed anything to try to get you permanent residence - and if so, when? If something was filed for you before April 30, 2001 and that case was approvable when it was filed, you may be eligible for 245i - a penalty provision which lets you apply for a green card from within the U.S. without leaving by paying a fine. You would need a new petition, by a family member or employer-sponsor, but could use the old petition for 245i eligibility so you could process here.
Your father could file a case for you as a permanent resident, but this would take a long time before you would be eligible to actually get a green card this way, and you would need to process out of the U.S. (so, you would need to leave before 180 days pass from your 18th birthday so as not to be subject to a bar). The other question: could your father be eligible to apply for naturalization (U.S. citizenship) soon? If he can get citizenship, and then apply for you with enough lead time before you reach 21, you may be able to get a green card this way under the immediate relative category. It would be something of a long shot to get everything through in time, but worth exploring.
Final possibility: there is proposed legislation called the DREAM Act which is intended to help people in exactly your situation - but although it has been introduced in congress many time, it has not yet been passed into law (and if it were, we would need to review the final wording to see if it helps you or not; might only apply to people turning 18 prospectively and may only end up applying to people in four-year educational programs).
Again, speak with a lawyer about the specifics of your own matter. I wish you all the best!
Some extremely urgent issues exist. You 'recently' began to amass unlawful presence in the U.S. The days unlawfully spent count against you ONLY AFTER an alien turns 18 years old. Contact an experienced immigration attorney, soon! Otherwise, you can be legally barred from return after you remain 180 days after reaching 18 years of age and depart the U. S. However, there are other issues. These challenges can also determine whether you can ever return and how long you must wait for a family based visa. Ultimately, you and your friends should fight for passage of a DREAM Act in Congress that will cover your situation.
U.S. Visa law technically bars you from attending community college without a valid F-1 Student visa. It is unclear how you were allowed to enroll in school. The opportunity to attend community college requires lawful status in the U.S. However, getting such a student visa due to the situation can prove extremely difficult at best.
There are other issues that may help. You may have been 'grandfathered in' based upon an application filed by your father, a relative of your father, or an employer of your father. This means that you may be allowed to pay a penalty. This is where you were directly or indirectly sponsored for immigration successfully mailed before or on April 30, 2001. However, this can get legally complicated, since some may still be unqualified for permanent resident status for other reasons. An experienced U.S. immigration attorney should know whether you qualify.
The issue of becoming a police officer in the United States is not legally possible. You must prove that you can lawfully work. All employers are required to have a new employee fill out a form I-9. The new employee must provide the proper form of identification to confirm that the employee can legally work. All employers, including municipal governments that hire police, are required to have a responsible form I-9 verification system in place. It is against Federal civil law, and possibly criminal law, not to properly elicit documents to complete a Form I-9 for new employees, even those who appear, claim, or insist that they are U.S. Citizens. A misrepresentation on a Form I-9 can cause serious consequences for both employers and those trying to lawfully immigrate.
A U.S. Citizen, a lawful permanent resident, a work visa holder, and those who have work authorization approved by the USCIS can lawfully work. Tourists cannot lawfully work, among others who entered without inspection. Some, such as an approved visa petition beneficiary (candidate) with a current visa 'may' qualify to file to work. A current visa petition is an approved visa petition filed before a specific date ("priority date"). The State Department's Visa Bulletin lists various categories of visas and the respective priority dates. I recommend that you speak with an experience law firm that concentrates its practice in immigration and visa law. An experienced attorney may help you to decide what you will do.
The above is general information not meant be advice. If you do rely upon it and the information does not apply to you or you misunderstand, you, among others, do so at their own risk. Often, the details in a situation determines what is the best option. An attorney who does not know the details cannot provide legal advice, only general information. This means that an attorney must encourage those with questions to seek an appointment or teleconference with the above mentioned attorneys, which includes our office.
Often, an immigration and visa attorney will charge a fee for such appointments or teleconferences, where a reasonable amount of time is spent. This is done because immigration and visa attorneys rarely get paid from legal insurance or the proceeds of an insurance claim. Also, because it can take time to ask enough questions and explain why action should be taken.