im really concerned over this

this is how i remember this situation, ill tell the story to the best of my memory, considering this was 6 years ago |when i was 13 and brother was 8 i was lying on couch sideways, so i was taking up all the space. he wanted to sit where i was and i jokingly said he should kiss me for that. it was just a joke and there was nothing sexual behind. no sexual intent or gratification just me trolling. i didnt physically force or restrain him but basically he hesitatingly leaned in and did it. then i probably got up and left. i dont know why i did that tbh, im not gay or anything, i was just being stupid and not really thinking straight. and like i said there was no sexual intent behind it it was just me being dumb is this SA or something illegal, or am i over reacting and is this just stupid kid shit im also aware he told mom once when it first happened and some other time a few years later which is stressing me out the more