If you book now, you will be quoted the highest rate for 2018 for that resort/room type, which will automatically be adjusted once the 2019 rates are released. If you will be going regardless of discounts, it's not a bad idea to book early so you get exactly what you want (especially since it's spring break time). With that said, if you will only go with a discount or want a package, it doesn't really help booking now. If you book RO now with the intent to change to a package later, the RO will have to be cancelled/refunded and a package booked, requiring a new deposit. Since RO and packages are different reservation systems, money paid toward one cannot be applied to the other.