Fit into what? If they already are your friends, then whatever you do or don't should be acceptable to an extent. If you don't know the lot, is that what you want to do to gain their friendship? That is silly.
I think it is cool to say no and not pressure your friends to do it even if you KNOW they would love it and you would like someone to share the experience with you. I have been someone's "pusher" once and it doesn't feel good on the comedown.
I get high because I want to. I have turned down offers of drugs I wasn't interested in. I have backed up others who did not want to and the rest of our group was teasing him in to it.
The try hugs not drugs and drugs will make you cool are reserved for the school age set as said before. I would however feel a bit of shame if everyone I knew, knew what I involve myself in. 'Oh the disappointment," they would say. I would say, "sorry about that, now fuck off."