Welcome!
Don't feel bad about not knowing until now something that you didn't know.
You'll probably be seeing signs that you and your family missed for a few more months, and it takes time to accept that they were missed, or perhaps noticed but not given the attention they might have needed. But everything is always easier "in retrospect". I see it as looking at a full picture and wondering why you couldn't connect the dots; but the thing is, the dots were part of the picture and couldn't be seen until somebody says to look for them.
I saw so many more things after my diagnosis (still do, in fact), and while they look obvious now, when considered separately, they would not have been seen as more than eccentricity or rigid ways (also, I wasn't that different from my family, so sure, I diverged from the norm, but not from my family's norm because it turns out they're a bunch of Aspies on both sides, hence no way we could have thought something was up).
Here you'll find plenty of answers, plenty of people with similar experiences, or with slightly different experiences, and you'll be able to learn from the diversity of our profiles, just as we will probably learn from you. It is a welcoming, accepting, helpful place, really, and I'm sure it will be a great tool for you to adjust to having a name for an aspect of you that was there your entire life.