I think that college students make good mentors, I went back and mentored my old team when I was home on co-op my sophomore year and it went well. BUT, I think that it needs to be in combination with other adult mentors. College mentors are good because they give a different perspective than a practicing engineer or a parent could, and the HSers can go to them for questions about college apps and college programs and how college is and such. But a college student is still a student and I think still needs some guidance and first and for most is a student, so they can't do alone, as much as they want to try.
With the Drexel FIRST Robotics club, I'm actually quite proud of my group, since they decided at our last meeting that for next year, we are not going to start our own team. They feel that we would be more help to the Philly area teams if we mentored the existing teams rather than start our own team. So my plan to stay involved in FIRST in college is to mentor needy area teams and volunteer at regionals, rather than start my own team. Engineering isn't easy (esp.when you're doubling in EE and BME like me), and I tell everyone in the robotics club I understand if they don't have the time to mentor a team, but they want to stay involved. That's what volunteering at a regional, or an FLL tournament, or an off-season comp is for.
