Pretty sure if you wait until after graduation to do ODS that time doesn't count towards your 4 year commitment, but you will still get the active duty pay I believe. Also most people in the Navy don't get to do ODS before school starts. I wanted to but they wouldn't commission me until Aug 1st, even though I was awarded the scholarship in February. My buddy in the Army commissioned in August too though but was still able to do his training the summer before school started. Bad policy in my eyes since a lot of schools (like mine and OP) only give a 2-3 week break during summer so I'll have to wait until after graduation too.