Absolutely not. Self-Diagnosis is valid. Self-diangosis is generally accepted within the autistic community. Due to multiple barriers (some of which you may have already experienced- misperceptions about autism, gender bias, financial  barriers, etc) an autism diagnosis is not accessible to everyone. An official diagnosis does not make you become autistic, it is confirmation of your identity

Some individuals seek an official diagnosis for clarity, if they have always wondered about reason behind their differences in perception, communication, reasoning etc. Some people seek an official diagnosis in order to help them  access accommodations.

Enter the Spectrum was created by autistics for autistic. I do not only view autism from the outside looking in, but understand autism from the inside.

You may consider another clinician depending on your goal. I am a Licensed Speech-Language Pathologist and Certified Autism Specialist. It is possible some places may prefer a diagnosis from a medical doctor/psychologist/neurologist.