BEGGING FOR ADVICE PLEASE

So I kissed my brothers best friend last night and I’ve fancied him for about a year and my brother was totally chill didn’t care as long as non of his other mates find out, perfect right. Issue is I have really started to like him and just don’t know wether I should just grow up and get over it (proving difficult) or pursue what could be an amazing relationship with him? I love my brother so much and would hate for him to ever lose a best friend :( (made this sound like we’re School kids were not we both have jobs haha)