Yay! have a great time, we will be there two weeks after you......we took DD to WDW the first time when she was almost 21 months.....she did great the first two days, just napped in her stroller, went on a few rides.....carosel, dumbo, train. she loved toontown and all of the character greetings, Pluto was a fav, she kept trying to get his tail.
2nd day did AK, her fav was the Lion King Show, we sat by where the Bird Lady came out and DD went nuts over her, they kept blowing kisses back and forth until she had to go on stage. We took her on the safari, pocahontas, tarzan rocks, camp mickey & minnie.
The 3rd day we stayed at the hotel (CS) swam a bit and gave her some down time and then went to Epcot that evening for dinner and illuminations.
4th day we were at the golf course builders convention (DH profession)and also did Chef Mickey's.
DD was a great sleeper/traveller before we went to WDW and always happy to be in her stroller, on daddy's shoulders or holding our hands. brought her lots of her fav snacks, water cup and her minnie mouse (never let that go) also brought a light blanket.
I loved our first trip with her probably the most out of all of our trips, since it was her first and seeing her eyes light up at everything was so magical.
Overall, take it slow, don't try to squeeze everything in and just enjoy the trip.
Have a great time!