How do I, 23M, communicate this to my partner, 24F without making things worse?

I, 23/M and my significant other, 24/F, have been together for 8 months. I love her, and we decided it was the right time to include physical intimacy in my relationship. We’ve fooled around before foreplay, making out, but never actual penetrative sex, and everytime I feel like ive been forcing myself to do it for her, and its been uncomfortable for me. Anyways, she’s attempted to initiate sex with me five times in about a week and a half and I’ve had a different excuse every time because I can’t bring myself to attempt to communicate this with her, and it has led to her no longer initiating anything physical.

I don’t know how to put it, but male sexuality (the sexual aspect of being male) just feels kind of gross to me? I have a relatively high libido, and i desire physical intimacy, but at the same time I don’t because it just makes me feel like the inside of a dirt cup if that makes sense, it makes me feel ugly/disgusted with myself and with my body.

My climaxes aren’t particularly anything to speak of in terms of sensation due to reduced sensation in my nether areas, additionally when I become aroused if she’s playing with me it makes me feel gross inside, like I’m using her, even if I’m not, even if it’s something she’s doing for me because she wants to. I would compare my experience sexually to smoking a cigarette, just much shorter, and on top of these struggles with my displeasure for the sexual aspect of being a male, in addition to feeling meh over my sexual experiences: Basically, “muh, rub nethers=feel good,” which already makes me feel stupid, I also have quite severe performance anxiety over my first time with due to it being my first time with anyone outside of just fooling around. I already know im not going to last long, and I’m pretty sure my anxiety over the matter is going to prevent me from getting hard to begin with, which the anxiety of that is enough in of itself to prevent it on top of these other issues I’ve described.

The biggest problem I have, is I don’t know how to effectively communicate this with her and I feel like shit for turning her down because it I can see she’s getting dissapointed especially because it was something that we both agreed on. I’m sure this probably stems to religious trauma and other traumatic events from when I was younger, I just don’t know how to tell her this without making things between us worse. How do I effectively communicate this with her?/How should I handle this situation?

I should also specify I have tested for Autism as was told that I likely have it, though I have not shared this with anyone.

TL;DR My SO and I decided to include sex in our relationship and due to my personal problems which I’ve tried to avoid making hers I believe I’ve inadvertently hurt her emotionally and due to difficulties related to my autism (she doesn’t know about) I have no idea how to communicate these problems to her because i feel as if It’s will ruin things if I do. Advice is welcome