I’m unsure about something I did as a child and I have no one to talk to about it

Tw: mentions of cocsa

I’m 17f (almost 18) and when I was around 10 years old and my brother was 5 we were outside playing truth or dare and I dared him to let me kiss him. He said no and I walked away to go back inside the house. He then said he’d changed his mind and I asked him if he was sure to which he said he was. I then quickly kissed him and walked away. Afterwards he immediately went and told our mum because he was confused because I’m never affectionate towards him or anyone else. My mum asked him if he was okay and he said he was and to her he seemed completely fine.

I’ve been too anxious to talk much to him or anyone else so my mum has asked my brother just a few times if he is okay about it and he says he remembers it and is. He finds it ridiculous that I’m worried about him. For ages I think I had a false memory surrounding the event in which I believed I had pressured my brother into it, but I know now that I didn’t. Since I realised that, I stopped worrying about the event for a bit but I’m scared again that it was cocsa because my brother and I have a five year age gap. I think it would have been even weirder if I had sexual intentions at the time but I’m still scared. I didn’t want to kiss him I just had the idea because I experienced cocsa when I was 6-7 years old. I don’t want the event to not be defined as cocsa just because I didn’t have sexual intent though. Was it automatically cocsa because of our age gap?