What to do?

My friends are going to hang out, smoke weed, and drink, and I'm debating whether to go or not. I have never smoked weed and I told them that if I go I won't be smoking.  I have however, drank although it was about a year ago since the last time. I'm a little worried that I'm going to get totally drunk because it's been so long.  What should I do? Btw I'm 13