Yes, she has hairy armpits. No, it's not a good idea to bring them up and say they are "gross". You would prefer to be shot in the head instead of falling off a building.
There's nothing wrong with not liking armpit hair on a woman, in the same way there shouldn't be anything wrong with a woman not liking armpit hair on a man. It's personal preference, and I have to agree, I find it gross. Really love the art style though.