Hey, you know some things about teeth, right? I had 3 of my wisdom teeth out 5-6 years ago and they said I was missing the last one - but now it's coming out. Was it hiding?
Nah, that’s just delayed development!
Tooth development is weird. The crowns actually form first, then the roots! Kids have these horrible little nubs of enamel floating around in their jaws, it’s so weird.
Teeth typically develop on a predictable timeline (so much so that we can use them for aging a skeleton), but because Biology Is Weird, sometimes you get premature development and a person’s teeth come in early, or sometimes you get delayed development where a tooth comes in late. It’s almost always the third molars that come in super late because they’re the last to form and your body can say “nah” for whatever reason. In genetic agenesis, you don’t have the ameloblasts/odontoblasts (think like, the Play-doh fun factory, except for teeth) to even make the teeth- yours just took a while to kick on! Specifically, I have a feeling it was your ameloblasts, which make enamel- you can see partially formed teeth in x-rays, so you probably didn’t have the enamel nub, otherwise they would have seen it.
(Also, I hope you don’t mind that I published this- it’s a really cool question!)