Hi, Wandalie!
I'm so happy to help you plan your first visit to Walt Disney World Resort with your two kids. A trip to Disney World with kids is magical.
There is so much fun to enjoy in the parks for all ages, even preschoolers. The folks at Disney Parks even put together this
handy guide to visit with little ones. You can also take advantage of
Rider Switch, where adults can ride on attractions even if there's a little one who can't ride it yet. My older child had a chance to ride some attractions twice when his sister was too little. It's an extra perk to being the older kid on a trip!
I always considered
Dumbo the Flying Elephant one of our favorites when our kids were in two different childhood phases. There's something silly and fun when you're flying around with an elephant!
Be sure to ask for First Visit buttons when you get to the parks so the kids can celebrate their first time at Disney World. I know it's going to be unforgettable!
Let me know if I can help with any additional questions before your March visit!
-Jen