As a relatively recent alumni-turned-mentor for my team, I can safely say that there is validity to every point that has been made so far. I should warn you now that this is a long post--I have lots to say on this subject!
Our team has a large number of graduated students that have come back to mentor, and it's been my experience that it takes about a year for most of them to grow accustomed to the change and really shine in their new roles. That goes not only for the mentor in question, but for the rest of the team, who has to grow accustomed to seeing/working with them in a mentor role.
I waited a year after graduating to come back to my team, and I'm really glad I did. If you come back too early, all the students on the team will still remember you as a student and treat you as such. This is not constructive to anyone, since it robs them of possible lessons you could teach, and it contributes to the problem that other adults may have in seeing you as an equal(which is essential if you want to do your team the most good). In my case, there were several students a year younger than myself whom I had not gotten along with while we were students together--if that is at all the case for you, then returning to your team prematurely will do it more harm than good.
This is not to say that you should stop helping your team entirely--on my year off, I drew up lesson plans and planned out a summer workshop for our new members the next year. That idea turned out to be a huge help to my team--we were losing a lot of veteran members that year, and we had next to no student leads lined up for the next year. I was also with them for Kickoff and contributed some during our initial brainstorming sessions. A serious medical issue prevented me from participating during competition season that year, but I would have come if I could have, and provided advice if asked.
Another way that you can always help your team is to keep your eye out for FRC updates, useful CD posts, videos from other teams, etc. This is something you can do even after you get back to college: obsessively check the FRC Blog, CD, and other teams' websites. You never know when you might pick up some useful technique, idea or rule change that your team could benefit from. I can't even begin to count how many little changes we've implemented in the past few years simply because our students and mentors do this every day.
Whether or not you decide to become a fully-active mentor this season, there's one major point that you
must keep in mind if you want to be a good mentor:
Do not try to force your way into this position. You want your team to come to respect you as a mentor on their own terms, and that process cannot be rushed.
If you don't follow that piece of advice, you'll end up with mentors who dislike you and students who resent you--I've seen it happen many times on my own team.
All that said, I would suggest that you take a more backseat role this season. Look around at the dynamics of your team--I promise you that being in a mentor position will open your eyes to a lot of things about your team that you didn't know! Look at how the students interact with the mentors, and how the mentors interact with each other. Try to see if there's something your team can improve on--if you were in charge, what would you try to change for the better? See if there are any holes that need filling. For example, is your team short on mentors in one particular area? If so, now might be a good time to start learning about that area, and see how you can help out there. Becoming a mentor is a lot like becoming an active student member: you have to look around and find your niche--whatever area where you can be the most helpful.
Another thing you definitely want to do is find a more senior mentor that you can learn from--one of the best things about this program is that everyone is always learning, all the time. Mentors are no exception. Find an adult on your team whom you admire, and can seek to emulate as a mentor yourself.
You mentioned that most of your students are newer members this year--maybe you could hold a how-to session or two during winter break to help start them off on the right path? What about off-season events and community involvement? When I came back, that was the first thing I worked on improving for my team. Look at how the students interact with one another--are they a tight-knit group that could truly be called a team, or is there some friction between members? Try getting a few mentors together to organize some kind of team social event--a cook-out, dodgeball game, LAN party, whatever.
Something else to consider: You are in a unique position on your team at this point. You have enough knowledge and experience to be considered a mentor, but you are young enough to the point that the students can relate to you(and vice versa) in a way that isn't usually possible with some older mentors/teachers. If you handle this correctly, it will allow you to establish a great rapport with the students--they'll come to respect you, not only as a mentor, but as a friend that understands them as people. You can use this to work out all kinds of interpersonal conflicts, and after awhile, you'll be able to teach them on a level that you wouldn't have thought possible.
I'm not going to lie--the first year, the transition year, will be the worst. But if you can handle it with patience and maturity, you'll end up in the best place it's possible to be in on an FRC team. It's like a little Christmas each time a student comes to you with a question, and I can't even describe the feeling you get when you see kids succeed because of YOUR efforts
