It depends on your personal tastes and choices of what kind of friends you wish to have..ofcourse many professional writers, bloggers accept...
You're being tactful that's about it...however if you feel guilty of not being able to come out openly just do it she'll fall in line with...
I think you need to trust your instincts when it comes to people and situations. You can't really stop people from making assessments or comments...
Just tell them it's grown ups who do it as an expression of love..teaching her about human relationships might help you here...again condom,...
Don't look for friendships where it doesn't exist..there are some people called acquaintances so, keep it cordial. You happen to share same school...
I think a greater and better understanding of religious scriptures helps us to have an informed opinion...karma isn't you do good and get rewarded...