I hate me I got physical at 20

I hate me i got physical at age of [20F] with my partner [21M] I always have a mind set that I will do everything after marriage but no everything changed. What I don't want is exactly what happened with me. I m not to stop overthinking about this. I also told my partner that I don't to do before marriage but I also didn't stop anything and there is no force actions . We both liked eachother and know more than 6 months. I have no regret but still I don't why it affecting me. That's all my mistake in the end sometimes I feel guilty and I can't undo anything. Is something like this happened to u also? Wanna hear thoughts related to this