Our children generally hit puberty head on regardless of their functioning "age" capacity. We see the changes physically but we don't factor in that the hormones are buzzing the same as any typical developing biological peer.
We noticed changes in Elisabeth's behavior toward the opposite sex around twelve but we weren't thinking, "Oh, this is puberty" because she's generally happy-go-lucky. She just happens to be around a lot of males -- her uncles, cousins, and friends at school. In fact, there were so many other issues going on "puberty" took a back seat until she turned 18. When we started experiencing changes in her sleep habits, staying up later for example, then it all made sense.
In church, she would throw her chains behind her when she saw a cute college boy standing near her. She tips her head to cuddle if you get close to her. She loves to be held with your arms around her. She also loves when you hold her hand which is something she would not tolerate. It wasn't until I watched her "flirt" with one of the male volunteers at her school that I realized, "Uh oh, her emotional age is catching up with her biological age!"
And that's a good thing. Here's an article about some of options parents and caregivers have about suppression of menstrual cycle which isn't an issue for Elisabeth right now.