Good for you for wanting to stay involved with FIRST and help your team. A warning, though, there are plenty of college students who have found mentoring a team in a serious (multiple times a week) way wasn't good for their mental health or grades. You'll be plenty busy adjusting to college where the workload will likely be significantly higher than high school and the time professors spend caring about you is less. The work on your FIRST team will likely be FAR more interesting than some of the intro classes you'll be taking. That can equal trouble. Every person and team is different, just make sure you have your priorities straight.
This thread discusses this in detail.