There is a more up to date version but either buy this or go to the bookstore and just read the section you need. This problem is addressed but don’t have the book here.
https://www.goodreads.com/book/show/236679.The_Naked_Roommate
Because this will become someone that wants to get high or do something else that you don’t approve of.
I don’t have any issues with you standing your ground in something you believe in. But almost every college I have ever seen has students that are underaged that drink. Wait till the sports start and game day (depending on what school you are at).
But do you have the “right” to tell others what to do… No. But you made your feelings known what you will /will not do in a social situation very clear. So beware when your roommate chooses not to go to social events with you. Also what are you going to do when you see her at a party, drinking and she comes up to you with drink in hand?
As I tell people… Just do you. If she has a problem with drinking that might be another issue.
Also… It’s OK not to feel pressured to drink, get high or whatever.
Again, Just do you.