okay so I know lots of provate schools require you to enrol your unborn child - is that for prep entry only?

I want to send DS to Private School, but for high school only, so Yr 7 entry.
Do I still enrol him now? Am I too late? He's two already.

I am thinking I might ring them, cos its a Catholic School, and while I was brought up Catholic, DS is not Christened and unlikley to be.