Premature birth

My question is that my daughter completed 19 months today.  She was born prematured.  I had just started my eight moth when she was born.  I am in  much depression.  She still not able to sit independently.  She try to sit from lying pisition but cant' sit.  She is very much active, use to say mama, dada, dao, baba, saying few words more, but unable to sit independently.  She can walk using walker, but cant' stand independently.  We have checked so many doctors, but they says that with time she will be able to sit.  Please advice.

[SusieKlim]

I have a good friend that has a son that is 22 months, he was born full term and completely normal.  He did not even roll over on his own until 13 months, and he couldnt crawl or walk for a while.  At 21 months he crawled and walked within days of each other.  Now he is doing everything that a 22 month old should.  Your daughter is probably just taking her time, good luck!