Does lack of concentration and impatience conclude ADHD?

Hello doctor,

I am a 17-year-old and have been doing completely well until age 15. After that, I started struggling and discovered that I had many symptoms of ADHD. Is it possible that I have ADHD? It is harder to focus in classes. I either zone out completely or am too impatient and fidgety. I usually have to watch online lectures afterward because normal speed feels slow or gives enough time to zone out. I have difficulty achieving simple goals like opening a bank account or studying for an hour daily. I thought I was just not interested enough, but the same happens in other fields. I am very much interesred. My mom used to tell me that when I was a child, I would get so deeply engrossed in something that I did not even hear her calling me right from the next chair. I feel like something is wrong. Kindly help.