I am so sorry to hear that you are struggling. As an Ethiopian, I too understand what you are going through. I was even surprised to see a post by an Ethiopian person here. Our country lacks the infrastructure for Mental health services. I think it is also hard to explain to family and friends what you are experiencing.
Well done for recognizing and researching the symptoms yourself though and not ignoring it. I am 29 female and it is just now that I am coming to terms with the possibility that I may have ADHD (I highly suspect it- I am waiting for an appointment). I have struggled through University and work. But I am trying to put in place strategies to help me focus and plan better now. It is taking time.. but it is worth it. Please know that 21 is a good age to learn about this now and you can find ways to help you reduce symptoms. I am less likely to take the medication route-so I am learning a lot about the behavioural strategies to help with the symptoms. I’m happy to chat if you want and I am happy reccomonde podcasts that i find useful.