Let me start off by saying that you have done a great job for two years without a teacher. Personally I don't think you should give it up, but it is your decision in the end I guess. You chose very difficult pieces! Alright, I have never played any of these but I have followed along with a score in both of them. In the Bach I suggest to use more dynamics. It sounds like mf the whole way through. Sure, Bach never wrote in any dynamics, but that doesn't mean that they shouldn't be done. The only time you really get into problems is when you get those 32nds which aren't quite as smooth as the rest of it, but they really aren't that bad. Part of it is definately the piano. Anyways, my main thing on the Bach is the dynamics. The Shostakovich which is the third Prelude from his Preludes and his Fugues, I think you chose an ambitious tempo. Sure my score says 126 for the quarter note. But playing 16th octaves at that tempo can be a real pregnant dog. So I would suggest taking a slightly slower tempo, one where you can get all the notes. I really don't play much music like the Shostakovich where there are accents on every half note, so I really don't know what to tell you about dynamics, but maybe the accents could be different sizes.
Anyways, I think you have great potential and should continue. Maybe if you are really unsatisfied with it just take a break from it and come back and learn something else. I think personally you should play some of the Chopin Preludes, some of them aren't too hard and are really wonderful. Once again Good Job! You should feel good about what you have done. You can play a LOT better than a lot of my piano students that have been playing for two years.
Topic: 2 years and without a teacher (Bach and Shostakovich)