Is it rude of me to ask someone if they have a dad?

So there's this girl who has been going to the same class for like almost 5 years, and whenever she presents about herself, like an about me, she tells everyone how much she loves her mom and that her mom is her best friend and stuff like that. Or when we're just talking about daily random things, she talks about her cooking and spends time with her on the weekend, etc. Basically, she talks about her mom a lot. But she has never mentioned her dad before, like ever. So it got me curious for a while if she has a dad because she never ever talks about her dad.

And I kinda want to ask her if she has a dad, but I don't know if it's rude or not. It's just a simple question, "Hey, do you have a dad?" because I don't know if it's offensive or not. If she doesn't, then she might feel hurt or think I'm nosy or weird if she does have one. Because someone totally different once asked me if I have a dad, and I do have one, and I wasn't offended at all, but I'm not sure if I should ask her because people might react differently, so idk. Or should I just stay curious and not be nosy?