what should i do she might tell my mom ?
Moms see and hear a lot more than we think. It depends on how you were talking about the subject. But either way it might be embarrassing, but it is always better to talk to your mom first and foremost about subjects like that.
What wrong with taling about sex. I swear sex has been around for a long time and yet when we tal about it we all freak out and scream! Where you talking about having sex? Or just about sex, like a conversation about it?
Were you just talking about sex in general, or were you talking about having sex? There's really nothing you can do if she tells your mom.. I would advise you not to lie to her... and be ready for a talk. :)
Say that you weren't planning on having it yet, and talk to her like said by moe (: