Is it normal i havent told him im autistic

I was wondering you guys how I explain to this man i'm talking to that I am autistic.
I am open about autism on my private social media which he follows but i've never stated to him how it is so he can't be sure.

He knows I have social anxiety and that I have sensory problems. He has sensory problems too due to a accident with a head injury so he gets that but I think he thinks I am shy mostly. I think I should explain to him why I am distant sometimes and such. Like one of my friends did whom I didnt know was autistic the first time we met but who told me out of the blue in order to explain he can be distant due to that because of overwhelm but its nothing personal and explained a lot like that. We are very good friends due to that.

I get overwhelmed too. When it happens I isolate myself. If I cant be alone to rest I get migraines. I officially suffer from migraine which are triggered by stress and overwhelm.

I know this man wonders why I am distant and sometimes I dont reply to him or reply little. Its hard to explain but my brain feels so tired sometimes. In those periods I can still sometimes text with certain people. Those people are the friends who know the truth about me. I dont feel pressure to mask with them. I can talk openly with them and also they dont get mad if I stop responding after a while and continue responding the next day.

Ive tried to not mention autism to not make it -a thing- but it is a very big thing in my life and my familys life. I go to therapy often for various reasons. I dont like having to hide this from a person who says they want to be a close part of my life. I hide so much I dont even know what he does know about me but its not much but I guess he thinks he knows much but he has wondered why I am not more open.