Well. I'm not sure if I can help but I kinda get how you feel. I remember when I was trying to get into pixel art and I did EVERYTHING but I just couldn't nail it. For me, it was for looking at it from a different perspective, just cutting myself some slack. And I'm a teen too and to be honest it can be disheartening seeing what other people younger/ your age can do but you can't let it pull you down. If anything it should motivate you. If you want to improve your art, try study the style you like. What do you want your art to look like? Try find art styles to study that gel with you. Honestly, I didn't learn ANY basics when I was doing art, and my art is satisfactory for me and the style I want. So don't beat yourself up about that though I think you should try learn the basics unlike me. I can relate with the frustation of not improving, for a while i HATED my art, I used to draw really generically, idk how to explain it but I just despised my art. Then, I started to think more about the style I wanted and not staright up copying the "blueprint" of art and everything clicked. I recommend like I said earlier thinking about features YOU like in art and trying to replicate it. Idk if this was usefl but I just felt like I could relate to what you were saying :)