Premature Baby and development?

My daughter was born 6 weeks early and she is now 10mos. I am concerned because I feel she is not even doing what 8 mos babies do... She is able to get up on all fours, but crawls on her belly and she does get around just not what I would say a true crawler does. She also has no desire to stand at all. She will hold her legs for a second and then pick them up when I try to stand her up... Any comments would be greatly appreciated.