correction: it's the nominations on the sheet we'll be putting up on the noticeboard that counts.
don't let the time commitment put you off, even if you're a final year. there's actually not that much work involved in being on the committee, week to week. aside from the time spent paddling (assuming you were going to do that anyway), there's maybe an hour, tops.
and don't let money be an issue either. yeah, you have to be at everything, but (*shocking committee revelation*) we've all been paying half price for everything all year! mwahahahahaaa