No. but I'll explain a bit.

When custody is first decided, one of the parents usually becomes the "primary". If something happens, then either the other parent is considered or a third party can be considered. If they can't find the other parent, then they're left with a choice between a third party or the State, though sometimes those two are the same "thing".

So.

Now you have a situation where Mom was unfit and you weren't contacted. Ordinarily you can petition yourself and see what happens. Very often, you'll get custody....but if you're a complete stranger, the court can legally decide to leave the child where she is (this is more common than you might think).

The reason why it's not a CoC (change of circumstance) is because it's not a change in the child's situation but the court can overlook that if it chooses.

Make sense so far?