If you do decide to go for an assessment and tell people, please bear in mind that school, the SENCO, many of your friends and family and everyone else with an opinion who is also not qualified to diagnose autism is likely to tell you your concerns are unfounded because in their eyes he's "fine"
However, ignore all of them, because their opinion is irrelevant. None of them are qualified to diagnose.
Some GPs sadly aren't as clued up as they could be about the variety of autistic presentation.
You'll be asked about his early development, have a look at the MChat-R online test and try and think back to when he was 2 and see what the score is. These are typical of the questions you'll be asked when providing a history of his early development. If you have other children and have noticed his behaviour is markedly different to theirs at certain stages, make a note of it.
Lots of people don't understand the autistic spectrum, there are lots of myths and fallacies, these two links explain it a lot better than I can.
the-art-of-autism.com/understanding-the-spectrum-a-comic-strip-explanation/
theaspergian.com/2019/05/04/its-a-spectrum-doesnt-mean-what-you-think/
The waitlist for NHS diagnosis is 18 months to 2 years in a lot of areas, so the sooner you start asking for a referral from your GP, the sooner he'll be assessed.
More info from the NAS www.autism.org.uk/about/diagnosis/children.aspx
You may find as the demands at school increase the wheels start to come off as masking gets harder for them
This is so true, it's doubly hard if you have to start the referral process at this stage and it can happen at any age, there's no set time.
Also, if you notice he appears to be immature in some situations, this is great advice.
DS neurologist advised that as a general rule of thumb we should deduct a third off his chronological age and this would give us an indication of what sort of social and emotional stage he is at.