When you say mild do you mean high functioning? My DS is very high functioning and has a moderate ASD diagnosis. I guess the signs were in relation to his behavioural and social development and things ASD kids often have like sensory issues, low muscle tone, poor coordination.
Language wise there are no real issues, toileting we achieved a bit later but again with no real issues. Starting school was an absolute nightmare and has been ever since. He has not coped at all and is always branded the bad child. The school made absolutely no provisions for DS until I started complaining to the education department regularly. They neglected to seek funding he was eligible as well which is infuriating. Discrimination is rife and is generally accepted by everyone in education. I was personally threatened in regards to keeping my DS at his current school and even the education department had no problem with that. So I guess just be ready to fight constantly for your child. It's an absolutely exhausting nightmare.