My daughter is 12 months old, and doesn't like sitting - she was 11.5 months before we could even get her to sit in her pram, or high chair. If we try to place her in a sitting position she just arches her back until she is lying down. She can commando style crawl, but can not yet stand - even holding on. We have just started physiotherapy with her - and they say she can sit, as she has the muscle development, she just doesn't want to, so needs to be encouraged to sit. They have suggested some exercises for her to do - really playing with her in ways that will encourage sitting, and get her used to it. They have told us we need to get her to sit, before we start worrying about getting her to stand.
If you are concerned about your child I suggest talking to your child health nurse, and see what they say, and don't let them brush off your concerns as nothing. I'm sure that my child will eventually get there on her own, but figure that the mild physio she is getting can't hurt, and may help.
mum to 2 girls