I'm not going to volunteer to be the designated driver
Why don't you want to be the designated driver?
I don't want to be the one not having any fun.
It's not fun to have to be the designated driver, but you should take a turn being it to make sure you and your friends stay safe. You will feel really bad if you or your friends end up getting hurt.
Why would I feel bad? They should not drink if they don't want to get hurt.
But you should try putting yourself in their shoes. Wouldn't you be happy if one of them chose to drive you around so you could drink sometimes?