Anxiety and premature ejaculation are making me avoid penetration

I’m 19 and my girlfriend is 18. We’ve been together for 3 months. She had a serious relationship before me for around 2.5 years so she’s much more comfortable and experienced sexually than I am.

We only started doing sexual stuff around 2 and a half months ago. It started with hand stuff, then oral. The problem is that from the beginning I’ve been extremely anxious about it all.

The first time she gave me a blowjob, I finished in under 30 seconds. Since then, it’s become a pattern. Almost every time she gives me oral, I finish very quickly, and now I get into my own head before anything even starts because I’m worried it’ll happen again.

The other issue is penetration. We’ve tried multiple times, but every time I’m about to do it, I mentally freeze up and can’t go through with it. She’s genuinely patient and reassuring about it, and we communicate well, so the pressure isn’t coming from her. Honestly, she’s handled the situation really well.

What’s frustrating is that I think the anxiety about finishing too fast has now turned into anxiety about sex in general. The more I think about it, the worse it gets. We’ve tried different settings and taking things slowly, but I still feel stuck mentally.

Outside of this, our relationship is genuinely great. We’re affectionate, close, and comfortable together. This is just becoming something that’s really affecting my confidence and stressing me out.

I’m mainly looking for advice from people who’ve dealt with something similar:

• How did you get out of your head before penetration?
• How did you stop associating sex with pressure/performance?
• And did anything specifically help with finishing too quickly during oral?

Thanks in advance for any serious advice.