Once the State Attorney's Office officially drops the charge or files what is called a "No Information," you can begin the process to get your record expunged. You can do it on your own, but chances are an attorney can get it done quicker...approximately four months.
Like the other attorney said, the suspension is supposed to start once a person is released from jail or prison. However, in some cases, the DMV gets mixed up and it starts before their release. Your son will be eligible for a hardship licence six months after the suspension begins. Although not convicted of DUI, he must enroll in and successfully complete DUI school to obtain his hardship.
Yes, you can "date." Furthermore, should your conduct eventually progress beyond kissing, because your boyfriend is 16 and you are under 24, you cannot be convicted of sexual activity with a minor. And because he is 16, you cannot be convicted of lewd and lascivious molestation.
I would either hire an attorney or, if you can't afford a private attorney, ask for the public defender to be appointed. Depending on the reason for your license suspension, you may be able to get it reinstated (was it suspended because you didn't pay a ticket?). At times, the State Attorney will agree to drop the case or amend it to a civil infraction if you get your license back. The last thing you need is a Driving While License Suspended or Revoked criminal charge on your record.
There is a high likelihood that the warrant is still active and that you would be taken into custody on it once you enter the United States and go through Customs. As the other attorneys stated, your best option is to hire an attorney who can ask for the warrant to be withdrawn, explore any defenses you may have (including a Motion to Dismiss based on Statute of Limitations), and in general, help get this matter behind you.