Does my mum really not know...?

I think your mother does know what is going on but she trusts you enough to let it go a few times but just don't do anything you will regret because sometimes situations can get out of hand don't let anyone call you names like slut or because your a teen and I think almost every teen goes through this stage just becareful and don't do alot of things behind her back because she don't want to be strict she just don't want bad crap happening to you