Both of my kids seemed to be the most freaked out by Santa when they were 18months. Every year after that they were fine with him. We didn't go to WDW until my younger DS was turning 4 and he loved the characters. He was so amazed by meeting Mickey - like in total awe and so happy. It was the most adorable thing I have ever seen. I will cherish that memory forever. I do think every kid is different. Hopefully it works out for you and your little one this trip, but if not then that's an excuse to go back in the future and try again!!