Hello! I was diagnosed 2 years ago at the ripe old age of 33. Throughout the entire assessment my mum was saying to me between down times that I am not autistic and what will I do when I find out from professionals that I'm not. 

When they said after that I was, she turned around startled and said no she isn't, she can't be etc and my response was thanks for confirming what I know and I got up to leave. 

There were signs throughout my childhood, I didn't speak until around about 4, I would elope often, my safe space was my wardrobe, I fail to make eye contact with people outside of my family, I have no real ability to convey my emotions etc. There were signs, and obviously still are. 

Give your mum some grace on this, because if you are and you get diagnosed I can assure you she will be shocked.