I (21M) can't be intimate with my girlfriend (19F) after she made a comment about my penis size. How can I move on from it?

First off, this isn't a joke / troll post.

My girlfriend (19F) and I (21M) have been together for 8 months. We had our first bad fight last week, and in a moment of anger, she made a race-related comment about my penis size.

That's a low blow to any dude, but especially for me, an Asian American who had to deal with racially-motivated bullying until high school, it hit me particularly hard. Also, because I wasn't short, un-athletic, or smart, the small dick jokes were the default insult kids would use on me.

When she said it, she saw the look on my face and apologized right away. She said "you know your dick isn't small, I just said it to 'win' the argument." She wanted to make up right away, but I was pretty pissed so I left and told her not to contact me for a few days. She came to my place with food from my favorite restaurant and apologized again, so I decided to try to look past it.

Anyway, about a week has passed and she's been really remorseful and all, but I just don't feel like being intimate with her. She's the only one who initiates sexual stuff since then, and even though my body reacts to her at first, when things get started her comment just runs through my head. Earlier she literally jumped on my lap wearing nothing but a bra and panties but I still just wasn't feeling it.

I can tell she's hurt by me constantly rejecting her sexual advances, and she keeps re-assuring me and exaggerating, which makes it worse tbh. I'm not insecure about my dick size, I'm insecure because she knows about the bullshit I went through as a kid and said it anyway. My girlfriend is white / caucasian and has never dated outside of her race before, and I'm not sure she really "gets it." She asked me to explain my POV to her, and I could tell that she understood the words I said, but she didn't feel the sentiment behind them, if that makes sense.

Sometimes I feel like I'm overreacting because of my past and need to get over it / move on. We both really like each other and had crazy chemistry ever since we met despite being from very different backgrounds. But on the other hand, I feel like that level of disrespect isn't going to get easier to look past and might happen again. And maybe that's the way she was brought up, and her being attracted to me isn't going to change that. Either way, I'd never tell this to anyone I knew irl, so help me come to my senses. Thanks.

TLDR: Me (21M, Asian), gf (19F, white). We got in an argument, and she made a negative comment about my penis size to "win" despite being aware of my racial bullying as a kid. I've lost the desire to be intimate with her because of the comment.