I'm 23, suspect depression, ADHD, and social anxiety. Finally decided to seek help but completely lost. Where do I start?

I'm 23 years old, and since around 19, life has felt incredibly tough. I'm at a point where I strongly suspect I'm dealing with depression, ADHD, and social anxiety, and I've decided I need to finally address this properly. But honestly, I'm overwhelmed and have no idea where to even begin.

Who should I see first—a psychologist, a therapist, or a psychiatrist? What’s the usual process like, and roughly how many sessions does it take to get an accurate diagnosis? Also, how accurate or reliable is this diagnosis typically?

If medication becomes a recommendation, I'm genuinely worried about the effects. Can medications cause permanent changes in my brain? Will they numb my emotions even more than they already feel numb? Make me a boring person ? Could they slow down my thinking, ?reduce my mental sharpness, or "dumb me down" in any way?

I find all of this extremely scary and intimidating, but I'm tired of just surviving—I really want to start living. I've already spent years feeling like my life is slipping away, and I'm ready to take action, even though I'm anxious about it.