Unless you are sure that you are not able to fit it into your schedule without going crazy, I say go for it. I interviewed for a peer advisor position at my university recently but did not make it (there was a lot of competition), but it is something I would have liked to done and you would probably enjoy it.
I understand how overwhelming school is, but if you think that it's a good experience, you should look into it. It's probably not that much time in a week to do, and you could always cut back on your work hours if need be. Just look at it this way: the sacrafices you make now, will be the benefits of the future.