Is this normal childhood experimentation?

First off, I'm heterosexual, but a long time ago, when I was about 7 or 8 I think (I could have been younger though, not sure) Me and a male friend tried oral sex (It wasn't full-fledged oral sex more like briefly putting the tips of each other's dicks in our mouths). Anyway, this is something that I've felt ashamed and disgusted over for a very long time, starting once I got a bit older and realized what I had done. I suppressed this memory for many years and almost forgot it happened but recently it came back for some reason.
It feels disgusting and shameful that I have done something like this and I constantly have anxiety because of it. I've read that childhood same-sex experimentation is normal and while that made me feel a bit better I still can't shake the feeling that what I experienced wasn't really normal.
Also I've started obsessing over what people would think of me if they knew this. It feels like if I got a girlfriend I would have to tell her this and she would probably be disgusted and dump me.

Is this really normal childhood experimentation? And also if anyone has some advice for how I can stop feeling so terrible about it and let go of it that would be much appreciated, also do you think I would have a responsibility to tell this to my girlfriend if I got one?

And just to make it clear, I'm not a homophobe, I just know I'm not gay so it feels bizarre and disturbing to think about having done something like this.

Sorry if this post got a bit cluttered and unclear.