My advice, do whatever you are doing and do it well. That's basically Andy Warhol's definition of 'artist.' It makes perfect sense too.
If you can't write code, do the best you can to use or adapt what's there - while trying to learn and understand it at the same time.
If you can't create a perfect logo, keep trying. Study the work of others, what's around you and also what makes you a believer in design.
Practice makes you better and getting bogged down in the minutae so much that you can't move forward is death.
A lesson most design schools teach...produce, produce, produce - even if it sucks, it will get better (if you are actually trying that is).
And finally, don't listen to what people say. Many great designers and programmers never had a lick of formal education - it's a good thing to have though. But, half the people will hate what you do, half the people will love what you do, and the third half won't even notice or care (you do the math on this one). 😉
Good luck...let us know how you are doing...v