I had exactly the same thoughts when I learned it and in fact I would have given the exact same analysis when I was at your stage. I urge you not to be intimidated by the speed you hear people playing the piece. I know from experience that you will actually be able to achieve a greater speed than you think you are capable of. I suggest consistent careful practise (which I am sure you are doing). You will achieve these speeds (or at least an acceptable speed) it is just a matter of when. Stick at it believe me.
O.K. I have time on my side... I'm retired. I will continue to work at it and other pieces that I have always wanted to play. Thanks again for your help.Mike