We start Kindergarten at 5 where I live. Sometimes you can get in at 4. Usually 4 and under is pre-school (I never attended. I actually got booklets from the store to do. No wonder I'm a school nerd.)
There may be differences in where you are in Canada, but I know here you are assigned to start school depending on the year you were born.
Sounds the same as here -
My parents tried to get me in when I was 4, since during the school year I'd turn 5 (start in September as 4, turn 5 in February), but I was denied and had to wait until the next September.
In Japan they start their school year in march. You then get summer break (not sure how long, think 2 months), then you get winter break, and end the year at spring break.
(Sakiko just graduated from university last month).