From my experience, it is very difficult to make a direct transition from a student to an 'adult' mentor with the same team. The team will be, in most cases, composed of most of the same students and mentors as before, but the new college student is expected to take on a mentor/adult role with their friends. This difficult interpersonal change is hard enough without the pressures of freshers year college. The degree means much less than the experiences that go into getting it and the jobs that come after.
My recommendation is to take a year off. College has much to offer and you should give yourself the opportunity to explore, and focus on your school work.
If you still feel the strong call of FIRST, it is much easier to transition back in as a college mentor after you have been away or involved in a limited fashion.
Wetzel