Aquafish, I understand your concerns. One of my grandsons always had certain strange ways about him. He became obsessed with certain toys but wouldn't look at others, he hated change of any kind. Would only have his toast cut in certain ways etc. For the first three years he wasn't interested in presents at birthday or Christmas (only wanted to play with Thomas) He knew all the numbers, colours and names of all the Tank Engine gang! but refused to move onto anything else.
To be honest, I wasn't worried, I just thought it was...him! My D and SIL were significantly worried that they did seek help/advice from professionals and he sure has had some extensive tests, but seems almost impossible to identify Autism until much later.
He is now six and there is definitely 'something'. He is absolutely gorgeous but is very much behind his peers academically and socially but he has still not been diagnosed as such.
Although he now interacts better and is more amenable to change, he still will cover himself up and go into 'quiet time' when all the other kids are playing (we have a large family of young GC) He will play for as long as he wants to and then toddles off to be by himself.
D is frustrated as she feels he needs 1:1 help at school but so far its been refused (see how he goes, type of thing). Because he was verbally challenged he would hit out if other children tried to muscle in on what he was doing. The school were very helpful but my D was constantly being told of his 'behaviour' . She was frightened he would become a bully. He seems more able to control himself now but still poor speaker.
Its inspiring for me to read about other's who have overcome autism to go on to University etc. I just want him to be happy and do as well as he can. When he is with me he is fabulous and I love him dearly but I recognise he ages with the 3 year old rather than the 7 years old but he is a big boy so people expect more from him.
I think all you can do is wait and see t.b.h. As someone else said I think we are all on some sort of spectrum! In the past, Autism was never mentioned.
Take care