GIRLS PLEASE HELP! Am I overreacting over something a girl said?

Ok, so I have alopecia(hair loss), had it since I was younger, most people can't tell and just think I shave. Well my crush made a comment about two months back abut having very smooth arms(cause I don't have much body hair) and I told her and she was surprised and said she never knew. She has been flirting with me a lot recently and I'm pretty sure she likes me. Anyways, one of my friends girlfriends brought her friend who I overheard ask my crush if I had anything, and she explained to her what alopecia was. I just blew it off and made it like I didn't hear anything but since then I've hurt that she asked, I guess I'm kinda insecure about it so for an attractive girl to ask it kinda "hurts my ego" so to speak. I know my crush doesn't care but just to have an attractive girl ask kinda hurt. Is it wrong to be a little upset over this, am I overreacting here?