My kids are bigger & taller, etc too. My DS1 has evened out lately. He's still tall but it's good that in his class there are a couple around his height so he's not all alone with his height. Lol. He's also slimmed down too. As he grew up he kinda evened out his weight.

DS2 actually got a comment today about not being at school. I was like "he doesn't go to school. He's only just 3" said with a smile of course. Lol.

Not sure how big is too big though.
If there was anything to worry about your MCHN would have mentioned something, right? ( Trying to put your mind at ease if you're worrying or something.)