I'll be in WDW staying onsite at CSR July 31 - August 6 and staying 1 week off site at Cypress Point (Aug 6 - 13). I just booked last week. So its not too early. I would just book to make sure you get the room you want.
Around Jan (looking back at Disney history) they usually release end of April - July codes/sales. August sales usually are not released until like the end of June. Disney usually has just August codes then the Fall sales are released. One of the reasons we booked for July was because I remember July having better sales and we missing those sales by some days of our arrival. So I figure with Disney having the policy that your first nights stay is your entire stay price I figure I couldn't go wrong booking the last day of July going into August