16 month old late milestones

[Lesleyann24]

Hi, my 16 month old daughter has been very delayed in all her milestones. She only started crawling at 15 months old. She does not speak or babble at all really, she only really says raa raaa sometimes. She is very social and loving. I also have a 3 m/o daughter and i have noticed extreme differences between them already, my 3 m/o babbles and smiles all the time, she kicks her legs holds toys follows you around the room with her eyes ext however when my eldest was the same age she rarely made eye contact whenever she looked at you it seemed more like she was looking through you, she never smiled until around 5 months, she has never babbled, she never kicked her legs about. She doesnt try to get my attention or show me things. She never cried as a baby, and even know she very rarely gets upset and when she does there is hardly ever tears.
We are due to see a paediatrician at the end of febuary but i am very concerned. Any help or advice would be appreciated

Thanks xx

[Littlesoul123]

How Is she