Yup, you are a mentor now. If it feels odd now it gets even weirder when the last student who "knew you as a student" graduates. Then you are
old 
. Happened to me a couple years ago.
They did a neat segment at Chesapeake Regional. They handed the mic to Head Ref Steve Shade, Lead Inspector Anne Shade & Announcer/Emcee Greg Needel to talk about the transition from HS students on a FIRST team to engineers and mentors of a FIRST team. It made me reminisce a bit about meeting when we were all students and before Steve and Anne were married.