Go ahead and make your reservations just as soon as you know what resort you want and when your dates are, then start watching for any announced discounts or special deals. Then you can re-book your stay at the special rates. That way you will know you have the resort of your choice tied down no matter what else happens.
One place where you can see when the discounts have been announced in the past is at:
https://www.mousesavers.com/historical-information-on-walt-disney-world-resort-discounts/#codetrends.
Also, you can go to the WDW Resort web pages and go to the page for resort you are considering. Click on the price for a room, then click on "View Rate Calendar." You can see the price for the room for every day of the year. You will see that the price can vary quite a bit depending on the date. That may help you choose a time that will save you several hundred dollars.
Then once you have made your reservation you will know what the worst case is for your visit, then start watching for the special deals base on the web page mentioned above.
I don't know what your situation may be so far a using a travel agent but you may want to consider doing your reservations at Disney yourself and letting your agent make the rest of the travel arrangements. There are advantages to both. I love to do al my Disney arrangements myself, and since I make my reservations I can deal directly with Disney. If you go through a travel agent you may have to go through them to make any changes. But the upside of that is that some
good travel agents will keep an eye out for those discounts.
If this is your first trip to Disney World, come back here with your questions. People here are mostly friendly most of the time and you can get a LOT of your questions answered.
Good luck and start looking forward to having a lot of fun!