At what point in the relationship do you let them know?

Pretty simple. I’m overthinking haha. This isn’t even a possibility of a relationship because my disorganized self can’t decide if I want a relationship or not with this person?

Either way, because of how unsure I am but still want to have fun, when should I tell them about my diagnosis? Not that it’s an excuse but it really does help with understanding who I am. Ironically I don’t even know myself.