How good am I at masking?
I have no idea. When I was diagnosed at 53, I told a co-worker. It was a big deal for me. Explained so much. He sort of tossed it off, but then he told me, "Wow, I'm sorry. I thought you already knew. I thought it was pretty obvious." He is on the spectrum as well. So there you are.
As a teenager, my mom always told me to act my age (act normal), and I was flummoxed because I only knew how to act the age I was. In a way ASD is just another label, like introvert, shy, artsy, etc. Now I know I'm not alone.
In hindsight, because I did not know I should be masking, I'd say 5.
Some things like making eye contact I learned in school for class presentations. I absolutely hated class presentations. I cannot present anything if there is more than one person. My brain shuts down. Lots of anxiety. I knew that wasn't normal.
When I got a dorm room in college, it was on the special needs floor. I had no idea why. Sharing a dorm room was very difficult.