Why is it impossible to mask in some situations?

So yesterday me(24m, audhd)) and my family went bowling. When I wanted to get a drink at the bar I suddenly saw a girl I know. We know each other from parties and friends. The crazy part: she gave me a like on hinge a few months ago and I couldn’t match because her location switched to another country(semester abroad). I decided to wait till she’s back and then give her a like. She’s beautiful.

Apparently she’s back already. So when I saw her my brain shut down. I couldn’t smile, I couldn’t smalltalk, I could only do the bare minimum which means I paid and left. It was awful, I wanted to talk with her but I wasn’t feeling like a human that situation. It wasn’t a red face, a shaky voice or anything like that. It just felt like mist all over my brain unable to function at all. I’m kinda sad and I admit I’m really wondering how she thinks of me now…