I 29M have insecurities over sexual experiences of my gf 26F

Hi all, so this one is a bit weird.

I'm in a relationship for 6 months and am happy with her. Both of us had prior relationships before and I have had several hookups as well before. I'm not accusing her or myself here, I just wanted an outside perspective on my insecurities.

So me and my gf have a really healthy sexual life where both of us are able to cum and enjoy each other. Once while talking about exes, she accidentally told me her ex used to last an hour by switching positions and doing stuff in between and things. In my case, I'm able to only last couple of minutes and I have only been able to make her cum with my tongue and not by penetration. is that normal?

I don't have a problem with her past and this never caused me concern. This particular thing have caused me concern and I discussed with her and she told me she is happy with me and she enjoys everything with me. So it's not a her problem, it's a me problem and it's in my head.

How do I get these thoughts out of my head, any advise is appreciated.