As a mother who has only produced little babies( joked to my Ob that the third one was going to be a monster and nearly hit 8 pounds- he just laughed at me) love your gorgeous babies and tell people they are thriving.
My babies have never been long or huge but then my husband's family are all very small Irish people ( call my kids leprechauns) but I do feel proud when my babies get fat.
I do understand your concern at times- my brother, a rare tall person in the family, has a baby boy with his partner(her brother is 6foot 6)who is showing all indications of being HUGE(was nearly a 10 pounder). He has been heavier than my son since he was 12 months old and my son is a year older than him, 10cm taller yet lighter!
My nephew is gorgeous, he has always been chubby and will grow up to be a big lad- the only thing that frightens my brother is the cost of feeding him as he eats everything and always looks for more.
Big is beautiful as far as babies are concerned.