Is there a deadline to apply for osap at sheridan college?

I'm going to sheridan college in september and I haven't applied for osap yet as there is a problem with my dad's income tax. But I have paid the $300 down-payment for osap to defer my fees. I was wondering if there is a deadline to apply for osap or if I could choose to cancel the osap and pay by using the installments method? Any info would be appreciated, thanks.