I think one of the issues is that OP says they bring it up constantly in every interaction. Labeling yourself disabled and then explaining that to someone in a relevant context is different from telling everyone you're mentally disabled in every interaction. It also ignores the fact that many people on the spectrum are constantly treated as if they have an intellectual disability when in fact there is none present. Conflating autism with intellectual impairment is ableist and harmful, and one quick Google search of the term "mentally disabled" immediately returns results for intellectual impairment meaning that right or wrong, society generally regards that terminology as such.

With my son for example, he struggles with motor skills, social skills, and processing differences. However, he is quite smart and not intellectually impaired. However, it is not uncommon for people to wrongfully assume that because he can't put his thoughts on paper as well as others and doesn't talk much that he is intellectually impaired, which is hurtful and harmful. This is an important distinction that I think needs to be carefully made.