I was diagnosed in my mid 30s. I even managed a good grade on a physics degree, without assistance.

By my 30s I began to burn out. I got diagnosed mostly since I thought the meds would help. In practice, the CBT helped even more. For the first time I was talking to a professional who both could keep up with my thought process, and offer useful advice and methods. It's helped me unpick a good number of maladaptations I had, and so free up a lot of mental resources.

It also helps to know that I am not a failed horse, but a highly effective zebra.