Should I get my son assessed for ASD?

My son is 2.9 year old. He speaks 4-5 word sentences. Knows numbers till 20 and can go beyond with little help. Knows alphabets, animals, birds, fruit, vegetables, birds and several other things. He has also started writing a few alphabets and numbers. Knows several rhymes even the national anthem to some extent, recognizes lot of relatives. Good eye contact, follows instructions 90 percent of the times. He is also able to tell us when he is sleepy, or has to poop/ already pooped (not yet potty trained). He has started nursery and his teacher says he does not follow instructions at all and also repeats a lot of things she says, which he also does at home. What do i do? He has not been assessed. One of the doctor we visited when he was 2 on a random visit wrote something which i cnt get over. Please help and also what does the numbers mean, he did not explain.