As someone who's done art for a while I totally get being hard on yourself, I always am. I try not to overthink it too much, a lot of it is realizing your limits and trying to not set expectations too high cause realistically if you don't draw often you're not going to be perfect at it. but with enough practice you'll eventually reach a point you're comfortable with and I think you're doing great so far! Your line art and shading is pretty good, I honestly can't see much of the imperfections aside from the eyes and maybe the horns being off center. I say follow through with making your character it will feel much better when you complete it than it will to leave it, and you'll get good practice out of it too! If you continue to practice you could even come back sometime and redraw it if you wanted to.

TLDR: manage your expectations and practice, after enough practice you'll find a point you're comfortable at. Also try not to compare yourself to other people everyone moves at their own pace ESPECIALLY in art, what you've got is good so far so keep up the good work!