Do you have trouble picking up on flirting

I’m so bad at this lol. I can never tell when a guys flirting with me and think he’s just nice and think nothing of it until a friend points it out. I’ve definitely lost a lot of opportunities this way lol. Like once a cute boy asked for my snap so he could send me notes from class, and I told him to not worry about it because I didn’t need them 🤦🏼‍♀️ Didn’t realize until later on it was probably just an excuse to get my snap