What is a nice way to phrase this?

i am 15 and i have a new boyfriend and last time i had one alll the other kids at school took it upon themselves to rudely ask me "how far have you and ____ gone?" and i hate when they ask me because it really isn't any of their business!! but when i say that to them they are like jeez you don't have to freak out about it then its just annoying. so what is a nice to say, it is none of your god damn business. but without sounds like a huge *********.