Mum trying to understand autism

Hi I’m new to this forum and this is my first post.

my daughter mia is 3 years old and has just been diagnosed with autism. She is still non verbal and lacks all aspects of communication even though she attends speech therapy every week she still can’t say any words or give eye contact.

Mia has sensory issues and headbangs or self injures when she hears load noises , she also lines up objects a lot rather than pretend play.

mia also dosnt interact with her older sister or any other children, she dosnt like being in social situations or anything out of her routine.

i guess i would just like some help understanding her autism more and to find out more about the speech side of it.

thanks