If you were adjudicated an delinquent as a juvenile you cannot possess a firearm until you're 24 years old. No exceptions. I wouldn't give up on the career you want simply b/c you had a few problems as a kid. While you may have to answer for the juvenile arrests if seeking a job in law enforcement, most other employers would have no idea that you have a juvenile record. I say continue down the path you want but you can't have a firearm if your situation as I mentioned above.
Your adult record and juvenile record are two separate things. But to become a law enforcement officer, you would probably need to unseal any arrests. Further, those applications are really a truthfulness and character test. Have you accepted responsibility for your past bad decisions, and have you rehabilitated your character by doing good deeds and living the right path now? A good way to find out how difficult your career path is going to be is purchase a firearm and apply for a concealed weapons permit. If you are denied, you may be in school for the wrong subject.
Here is a website with lots of great information: http://www.fdle.state.fl.us/expunge.
In closing, I encourage you to keep your goal in mind and do your best in everything you do and you will be a success.
http://www.defendme.net | The response given is not intended to create, nor does it create an ongoing duty to respond to questions. The response does not form an attorney-client relationship, nor is it intended to be anything other than the educated opinion of the author. It should not be relied upon as legal advice. The response given is based upon the limited facts provided by the person asking the question. To the extent additional or different facts exist, the response might possibly change. Attorney is licensed to practice law only in the State of Florida. Responses are based solely on Florida law unless stated otherwise.
One way is to go and try to buy a firearm where they run the NICS instant check and see if you are a prohibited buyer. You must, however, answer every question on the ATF form or risk committing a federal felony. If they clear you to buy the gun, you know your record is clear. You don't have to buy the gun.
If your misdemeanor criminal mischief conviction is considered a domestic violence conviction you are barred for life from even possessing firearms or ammo. That means no hunting, target shooting, checking out your friend's new gun, nothing. You can't even be around ammo. The only relief available to you is a pardon. But ask an attorney in Florida (I am in California so I don't know the answer) whether it is.
Felony adjudications for minors do not bar you for life under federal law, but many states will bar you for a certain amount of time. In California it is until age 30. According to my colleague's response, it appears in Florida it is age 24.
You should never give up on your dreams. There is work in law enforcement even without firearms. But, whatever your decision is, at least confirm you are prohibited from owning guns before you drop out.
All my comments here are intended for general legal purposes. None of my comments here establish an attorney-client relationship with anyone. None of my comments should be relied on in taking legal action without first consulting an attorney.