yeah iunno shading after a photo is really easy and i could barely bring myself to actually post that here but i really want some feedback
What you're doing is an extremely good way to learn a lot about shading. The only thing wrong with tracing is that you don't learn anything about drawing from it (and that it's copying somebody elses work), but since you're more focused on practicing shading then tracing is a good way to skip having to draw something first and get straight to it.
The shading itself is really smooth and looks great imo. can only get better from here, and its already pretty good.