Yes of course. Its the age when they are curious about sexual stuff. Its better they ask questions on GAG about sex than asking their friends, because most GAGers are older, therefore more reliable opinions (sometimes ahaha), and less pressures tbh. Plus I believe they may relieve insecurities, such as when they ask questions like "is this normal?", "haven't kissed anyone yet", "haven't had sex yet, is it normal?" Its better than having them listening to their friends that (more so often) lie about having lost their virginity or kissed. Also, it allows them to ask questions that they want and need to know but may be too afraid to ask in real life.
And honestly, 13-15 year olds swear so much themselves there's no point in censoring any kind of profanity.
Although I can say that I don't believe they should ask things like "how do my boobs look?" cause, no just no, even if they were adults, just no, pls sthap.
I would however like it if my kids came and asked me questions about sex instead but I know that can be an awkward thing for some kids to do.
And people gotta understand that 13-15 year olds are very aware of things, and no, hiding things and keeping your kid as "innocent as possible for as long as possible" is not going to help. They gotta learn this stuff through the years as they grow up. And stop censoring shit cause other wise they will find stuff themselves (like porn, which sadly I already did at 8 years old by a friend), its better you teach them the right things than them learning things on their own (through friends etc), otherwise they'll end up very naive and get the wrong messages. And I'd rather my kid knows what sex is, what contraception/protection is and how important it is, than trying to hide the subject from them all together.