If I might point out, there are lots of kids in the same secondary school who are five years apart. I think it's important to know that especially people coming from different countries and different education systems may arrive at different grade levels and they may think of themselves as social peers, though chronologically they may well be five years apart. Again, that's the reason we suggest, as opposed to a hard and fast age rule, that it merely be a rebuttable presumption.
On March 29th, 2007. See this statement in context.