Bach and Chopin are two VERY different composers, and just because you are able to play Bach well, doesn't necessarily mean that you will be able to play Chopin well. what pet said is true. really and you said you have learnt Bach's Inventions and a few preludes and fugues but do you realize that the level of bach's inventions are a a few grades lower then chopin's etudes. Are you in Grade 8 ABRSM or RCM, if depends and even if you were a grade 8 abrsm student I really would'nt recommend chopin's etudes as they are of at least a diploma standard. Chopin's Etudes require very good/excellent technical facility, and high level of understanding, they are not pieces that you can simply learn and play well, even if you play Chopin well in General. You should not rush into it, wait till your teacher actually gives you 1 to learn.