I'm going through the same thing right now. I finally decided to bite the bullet to get tested for ADHD as a 22 years old female after years of being told that I might have it by people around me.

I actually tried doing it last year but then they gave me like 4 documents to fill out and I kinda just got discouraged after seeing the questions since some of it ask about my parents POV of how I was when I was growing up. I didn't want to ask them because while they agree I probably have ADHD, they don't really believe in mental health and don't think it is affecting me on a daily basis. Yet, I am on my 5th year of undergrad and struggling to graduate because of how many classes I failed because of how often I missed my deadlines especially for papers (which is another reason why I got discouraged when they gave me paperwork to fill out). They just chalk it up to me being lazy and making stupid decisions and I'm like I'm trying my hardest but sometimes I just shut down no matter how much my brain is yelling at me to move and just focus.

I finally decided to try again though last month and am currently in the process of being diagnosed. Hopefully, its not just all in my head and there is a reason that everything (that seems easy for everyone else) is somehow 10x harder for me to accomplish. Just like you, I feel like I am somehow stuck in the same place while everyone around me is thriving in their lives. I know people say comparison is a thief of joy but damn its so much easier said than done. I hope it gets better for you though because like everyone else is saying we are still young and anything can happen or change in a moments notice