I just got grounded for being catcalled

TW(?) Triggering content I think

So ye my mom grounded me bc a guy from my old class 3 years ago told me to flash him with "the girls" I told him to back off. One of them called me over and I was like "Ye hi guys how's it been since I left town?" And we talked to the one who called me over even called one of the girls in our class and let me talk to her but one of them. (I'm not sure but I think my old bully) told me to flash them. I told him I have dignity and to back off when I got back home I told my mom about it....I told her that I think it was the one that called me over...I can't recognize their voices anymore to be honest. I do wanna ask is it my fault? I'm asking bc ever since my mom grounded me I feel all dirty like I did something wrong...also turns out they were drunk which I did not know bc one being autistic means I can't pick up social cues as well and two I don't drink so I had no idea...one of them told me he'd squeeze them and I told him if he tried I'd call the cops on him for harassment...I just need some advice or somebody to talk to bc talking to my mom leads to this...she says that we talk openly but I hide so much from her bc of times like these