Should I secretly get tested?

Hi!

So I'm 17 years old currently, and I've been worried for a long time if I should get tested for autism. My ex-best friend had an autistic little brother and frequently compared our behaviors, and they even made a list of my behavior that they considered strange:

-difficultly with deadlines -socially unaware -unsure of the rules when talking to people -confusion between platonic and romantic relationships -extreme sensory issues -hyperfixations -unusual eating and sleeping habits -unhealthy relationship with body - huge change in facial expression -stimming -slight OCD like tendencies -depression and social anxiety -lack of social cues -Gastrointestinal issues -Lack of fear or more fear than expected -tendency to copy or mirror others behavior

I have diagnosed ADHD (I was tested and diagnosed in 4th grade). My family calls me 'special' or teases me for being sorta different. I talked to them about getting me tested for autism just in case but they just said it was "mild ADHD" and shut me down. The only person encouraging me is my brother who believes something isn't quite right.

I don't know if I'm too young to understand or something. I've been called weird my entire life or treated like a child because I don't understand. I just want honest opinions if I should be tested or maybe I'm just dumb or something.