Hey Carly! How exciting to be planning a March trip, and believe me I completely understand how overwhelming it can be. But not to worry, WDW has some great ways to help you starting with us moms here at the Mom's Panel.
First I would take a look at my budget, does it allow for a deluxe resort, moderate or value? Once you decide this why not go online and take a look at all the resorts. This can be found at
www.disneyworld.com You can see pictures of each resort's lobby, rooms, pools, etc. You can also get exact pricing online whether it be for rooms only or WDW packages.
These are the first steps I would make. Once you have a few resorts narrowed down, then please come back and ask us anything you want about those specific resorts. For instance, I can tell you if a deluxe resort is doable, then I would highly recommend staying at one on the monorail system given the ages of your children.
I hope this helps to get you started and if you have any more questions, please come back and visit us at the Mom's Panel.