So at the moment, I am about to do my grade 4 piano exam. I am a very musical person and on the side I challenge myself to do grade 6 pieces, etc... I only have 2 and a half years left until I leave school for university and I want to have finished grade 8 by then - so could I skip grade 5 and go to grade 6, 7 or even 8 like one of you said?
Not sure what happened to the rest of your entry, but YES! Skip away! Truth be told, you do most of your learning/discovering at home if you are keen and in love with music, and talented. Hopefully you have a good teacher who can make sure you are developing well technically. I did grade 5 as my first one, and then skipped to grade 8, and went on from there. If you are able and willing, then no reason to claw your way up the grade scale. Too expensive.