I'm going to learn Rach 3! Am I crazy?
No, you aren't. Sometimes we listen a piece and we instantly have the desire to play it. This is good in some sense because means that we have a taste and music interests to us. But there's a real problem when we want to play a work we are not prepared to yet. Reading your first post, I don't think you are prepared at all to play this monster. You said that you didn't play even classicist music (did I understood well?), no speaking about romantics. So from that point of view, the answer in my opinion is yes, you are crazy.
Difficulty is always relative and subjective, depending on many factors. But if we try to objectify or quantify them, from Rach 3 we have:
- It's a really long concerto. Not only in duration but also in the quantity of pages of music written.
- It's one of the most dense works. There are many passages with many notes per square inch
- Requires a top technique and a full domain of many aspects of it: double notes, ultra complex textures, polyphony, finger independence, octaves, succession of octaves (pulse), big chords, big jumps, fast finger passages, etc.
- It's very difficult to read.
- The complex harmony, form and melodies makes it difficult to be quickly understood.
- If we don't have enough experience, we may focus on the tree while losing the view of the forest, struggling to play all the little notes slow, difficultly, pausing and been unable to make the important things sound.
- The technique required to play something like this must be very well connected to the musical ideas. It's obvious that some mechanical abilities are needed but a musical aim is indispensable. If we don't have a clear idea of the musical result, we could misuse our energy. In my opinion music and technique are joined together.
Its a very grave mistake to attempt a work one is not ready to play. There's a big risk of frustration but even of injury if we try to play a piece for we don't have the adequate technique nor enough background or previous music experience.
I once talked to Bruno Gelber about this concerto (who plays this in a wonderful way) and he said to me that it was one of the hardest things he had to do on his life. He used several weeks only to finish reading the score. He felt like solving a puzzle, reading note by note. I think that if a great and experienced pianist as Gelber suffered to bring out this piece, I have not very much to add.