My (16M) girlfriend (18F) cheated on me with a rich kid. What should I do?

My (16M) girlfriend (18F) and I have been together for a little over a year. She just started college and works at this super expensive country club where all these rich people hang out. There’s this one guy (17M) who’s a member there, and he’s, like, stupid rich. Apparently, he asked her out, and she told him she had a boyfriend (me), but then he said he wouldn’t tell anyone, so she went out with him anyway.

This dude picked her up in a freaking Lamborghini, and they went to Ruth's Chris for dinner. I’ve never even been to a place like that because I’m just working part-time and trying to save money. We usually just go to the movies or eat at normal places. Anyway, after their fancy dinner, they went back to her dorm, and yeah, they hooked up.

The guy blocked her after and basically told her he wasn’t interested in dating her, and now he’s back with his rich girlfriend (also 17F) like nothing happened. My girlfriend told me everything because she said she felt guilty and thought I should "forgive her" since she was honest. I told her I needed time to think about it, and honestly, I feel like complete crap.

I talked to my mom (38F) about it, and she told me that if I can't forgive her, then I don’t deserve her, which... idk, feels kind of messed up to say? Like, I’m the one who got cheated on here. And to make it worse, my girlfriend straight-up told me that their date was better than any of our dates, including the ones where I actually tried. Like, I get that I can’t take her to fancy places, but it just sucks hearing that from someone you care about.

I’m just feeling really hurt and jealous, I guess. I can't compete with a rich kid who rolls up in a Lambo and takes her to places I can't afford. Should I just forgive her and move on, or does it even make sense to try anymore? I still love her, but I’m not sure if I can get over this. Any advice?