Do not worry about perfecting pieces just enjoy the constant learning experience, you can always go back and master pieces later your favourite pieces you have a lifetime ahead of yourself to practice them.
I guess... only my lifetime ahead is a bit shorter than some of the younger ones...

I do notice that some students get overwhelmed as I constantly put them at the start of the ladder to learn more and more pieces, I usually ensure that we at least sometimes do things they can easily manage and solve. There is no problems asking your teacher to do easier things with you to take off some of the pressure and allow you to see the final product more rapidly or even asking if you can get help polishing already learned pieces.
I guess I would already be able to learn easier pieces up to resonable standard myself, since we usually don't have that many spots where she nees to go into details to correct/teach something. But it's a time issue. Lessons are every week and not every week I have enough time to practice due to work... But having a lesson every other week doesn't sound that good either. I should have taken better advantage of all the free time when I was a kid and learned to play then

I do want her to keep teaching me stuff that is hard for me, and she seems to know exactly how, so I just have to manage...I have more productive and less productive weeks. It takes so long to just read the score and get the notes and fingerings even for the easier passages, so the time left to actually practice the more technically demanding stuff is never enough. I usually somehow manage, but it's always lacking the security created by enough practice, and that makes me frustrated on the lessons and frustration make sit difficult for me to focus...