It might be annoying at times but it's not a big deal. It's not going to turn me off. I think it's ridiculous to expect women to be ladylike even when they're asleep. If you snore, you snore. You can't help it.
I don't find it unattractive if a girl rips lots of massive, loud, loud, farts that reek and does it often or often poops massive poops, that block my toilet, reek and totally paint my toilet bowl in her poo so if I don't mind that I sure don't mind it when a girl snores.