Tiny covered everything I would have pointed out. I am also working on fixing a chair seat and landing in the back of the saddle instead of in the center. I think it's more a core muscle thing than anything else, but you're young so you have that advantage. You're going to be a very good rider when you get your seat and body parts under control. You do have very good self awareness. Your instructor definitely has you headed in the right direction. Keep up the good work.
You just have to see your distance...you don't have to like it.