My daughter will be 4 months old in 5 days and I've noticed recently she has stopped cooing, I'd probably say about 4 weeks she has been quieter than usual. However, she does squeal and make other random noises (blowing raspberries etc.)
She tends to stiffen her legs only for a few seconds when she gets excited or cries. I see other babies constantly move their legs when their excited. She does move them a lot during the day though, not only stiffens.
Also, her eye contact can be great but sometimes she can be diverted to something else mid conversation.
She looks at me on her jumperoo and sometimes she'll look away whilst smiling and then look back at me.
She occasionally gives eye contact when I hold her up but she tends to look at my partner next to me but if she's being picked up by my partner she'll look at me.
Is this normal? I've read online that if they look away whilst you are talking it could be an early indicator of autism? I know it's far too early but she had amazing eye contact up until 3 months and would only look at me rather than anything else in the room.
As for imitating faces, when she was a baby she used to stick her tongue out when I did but the only imitating she does now is if I smile at her. When do they start imitating?
Things she does do:
She smiles and laughs a lot. I only have to look at her and she gives me a big grin 
She follows objects
She grabs toys
She follows whoever's in the room
Noticed her hands, tries to grab her feet when in a sitting up position.
Can bare weight on legs
Please tell me what your lovely babies were like at 4 months old and if there's anything I should be worried about from what I've wrote.
As for the eye contact, should I be expecting her to look at me for the whole time I'm talking or is it normal for her to look away sometimes?
I hope I'm overthinking things but it can't be helped as bother of my brothers are on the spectrum!