Your friends will all be jealous when you show you were more mature than them by saving it for when you meet the right guy. Not just some random loser on the bus who doesn't really appreciate you. I'm sure you are beautiful.
Have you thought maybe your 'friends' are trying to manipulate you into doing something stupid they are too ashamed they have done themselves?
It takes guts to be different, but no woman I know ever regretted acting like a lady instead of a tart. Tho many regret being a tart, something they can't change once they do it. Don't give in to them, they aren't thinking of you, they are just wanting to not feel alone in their stupidity. You were smart enough to post here for advice, so be smart enough to take the advice you've been given.
Second thoughts can generally be amended with judicious action; injudicious actions can seldom be recovered with second thoughts.
--Cyteen by C.J.Cherryh