I missed this thread last week – hey, it’s like we have the same kid, only reversed genders. My daughter is also 3 1/2 feet tall and towers over her peers (and has a big head), and is routinely mistaken for 6-8 yrs old. She’s above 95% for height (although in the 80’s for weight – has slimmed down a lot). She is also advanced academically (can read, do arithmetic) which also makes people misjudge her age.
But her language and overall social development are delayed by about a year, by my best estimate. She has a good vocabulary but the way she talks is not quite natural, if that makes any sense – she tends to mimic exactly the way something has been said to her. But yes, we have the same issue where people expect her to act like a 6-8 year old and she emphatically does not.
Her physical coordination is also a little off. Some of this I blame on the fact that she is so large. But that’s not all it is, as she has peers who are almost as tall but who are much more athletic/coordinated.
A lot of things about her make me think autism spectrum, although when she turned 3 she was (on the advice of her caretakers, who were very worried about her – they were the ones who alerted me that her development was off) tested and they didn’t diagnose her. I suspect she’s normal enough that she doesn’t quite make the cutoff for a formal diagnosis, but enough sigma off normal that it’s plain to observation.
ETA: I was premature and always very small for my age; my sister was normal-sized all the way through. My husband grew up to be 6 feet tall but was a normal-sized kid, even slightly on the small side.
Both my nieces are tall for their age, and get mistaken for older than they are. However, watching the older niece play soccer last weekend, I noticed that while she’s still taller than most of her teammates, she’s not as noticeably taller like she was before, if you know what I mean. I think her peers are catching up, though it is possible that she’ll end up on the taller side as an adult - her dad’s average height, but his brothers are 6’3" and 6’5".
On the other hand, everyone tells me that El SpouseO was average for his height, even in junior high. He shot up one summer and ended up 6’6". (Grew so fast he still has stretch marks on his back, in fact.)
My son’s about to turn 2, and is something like 38" tall, and he’s just tall (I’m 6’1" and my wife’s 6’2", so he comes by it honestly).
He’s big too but not fat- he’s probably 75th percentile in weight and somewhere in the 90s in height, which is where he’s been more or less, his entire life.
Since there isn’t anything you can do to preempt the ultimate course of the child’s growth, the only course of action is to psychologically prepare the child and his family about the downsides of unusual growth, so they can deal with situations as they arise. To that extent, yes, one should be concerned whenever a child is in a very low percentile at either end of any developmental bell-curve.