A drawing is not like classwork: there is no pass/fail, no percentile, nor letter grade; a drawing is a drawing.
The only person grading your work is you, and you don't have to judge it if you don't want to. A drawing isn't good or bad: it just is what it is. When something looks the way you want it to, keep that part: when it doesn't, change that part.
If you practice, you will get better. If you don't, you'll get rusty. You climbed that mountain before, you can do it again.
As for getting started: Love to draw, hate the drawings: take pleasure in the act of pushing the pencil around on the page, regardless of what the end goal is. Enjoy the process, not the product.
As me mother dearest says: sit down, show up, tell the truth, don't censor yourself, don't focus on the results.
Finally, let me just say: no matter how bad a drawing looks, it will not kill you to make a bad drawing: as such, you are invincible as long as you refuse to give up. You hear me? You are utterly invincible, an unstoppable juggernaut! So get out there and draw! Draw 'til your fingers fall off! Let nothing stand in your way, destroy every obstacle in your path!