Should I bring it up or forget it ever happened?

Recently, an old childhood friend that I haven’t spoken to since I moved away about 16 years ago found and messaged me on Facebook. I was best friends with her and her older sister when we were about 6–8 years old and living overseas in Japan (our fathers worked together for the military). Once I remembered who she was (I hadn’t thought about them in a long, long time) I immediately remembered what I’m guessing was some weird suppressed childhood memory of us making out when we were girls. I remember it started as a kissing game I would play with her older sister but then she got “jealous” and eventually I would make out with her too. I distinctly remember these make out sessions being rather long and very physical with some dry-humping involved. Now that I remember, it’s starting to creep me out a bit. Is it normal for 8 year old girls to make out with each other? This was my first kinda sorta sexual experience, why didn’t I remember it until now? More importantly, should I mention it to my friend to see if she remembers or just forget it ever happened? :/