Do you have a particular reason to be concerned about autism? Maybe speak to your HV. For what its worth ds at that age didn't do anything (sat up at 10 months) and looked like ET. Perfectly normal 5 yr old now.
Thanks! Sorry, forgot to explain that I'm anxious because I already have a 7 year old dd who has classic ASD. She was quite slow with motor skills.....dd2 (NT) was very quick at everything and walked at 10 months. I am not worried because having a child with ASD upsets me but because it is so difficult to get decent provision for a child with such complex needs. I know it is all pointless though...
electra My DS2 has regressive ASD and when I then went on to have DD I was very concious once we reachedthe age when he suddenly lost all skills.
The thing is that I did eventually realise that watching her and fretting about it was bad for two reasons firstly once you start looking it is impossible to be objective so on a good day I would see NT and on an anxious day I would see ASD. Secondly - it is far more important for her development that I interact with her in an average normal way. Finally it is impossible to enjoy being a parnet when you are looking objectively at your child.
I know it is easier said than done but try and let it go. If there is anything to see you will spot it early enough to help her. If not then you will not have wasted all that time.
I have 2 friends with babies that age not sitting up. I think most autism experts believe you can spot what may be signs of autism from as early as 6 months but the margin for error is wide at that age. The only signs I can remember from that age is total lack of interest in what I or anyone in the room was doing and zero play skills. DS1(ASd) walked a little earlier than DS2 (NT) and there is no convincing evidence that delay in gross motor skills is co related to autism - unless it is being conflated with global development delay.