I'm going to interschool athletics , is the 200m running event all sprint?

Hey guys , Like i said , I'm going to an inter-school athletics event and I've never before chosen to do the 200m. Some of my friends told me that you sprint the WHOLE thing and some said you give like 75% until 100m is left then you sprint. I'm good at short distance but this year i chose 200m to be adventurous , I'm not that fit and the event is in 12 days from today , but there will be loads of practise sessions. So please can you tell me , is the whole thing a sprint ? do you need to be really fit? does it feel long? if i need to be fit , can i get fit in 12 days of playing cricket and 6 1 hour practise sessions? thanks :D