Trust me, there can be downsides to starting early. In my case, I virtually skipped having social interactions not on the internet until I was around 20 or so. Not everyone will have this kind of affliction, but you can't have it all - you gotta choose what's important to you. I hope this doesn't come off as being too negative, I mostly say this because I think you should try to appreciate what you did learn rather than lamenting about not being able to start with coding super early.

...that being said, this is way cleaner than any code I'd written at 12 I'm pretty sure.