Yeah, my school's a secondary school (British system), which means we go from Year 7 to Year 13 (i.e. 6th to 12th grades). I'm just putting 2004 as my year of entry. It makes more sense to me.
I think if you switched schools, you put the date of entry to the school you're going to at the time you submit the application - so RocknPiano, I would say 09/2010 is your entry date.