I complimented a stranger and it made me feel bad

I was at kmart going to checkout and i saw a girl around my age wearing a T-shirt of a show i really like, i got excited so i wanted to tell her that i liked it (I have bad social anxiety so i never do this) but when i did she didnt say anything and just looked at me with a straight face and slightly nodded, i literally almost started crying and i dont even know why, its just a shirt and a person i have never met in my life and will never see again.
Anyway im never complimenting anyone in kmart again