At 4.5, she should have some memories of it afterwards.
She has also been twice since being born. Shes been at ages 11 months and 15 months. At 15 months she was with us for a full week and we had a blast. She loves Stormalong Bay and apparently thinks the sand taste really really good. 
). We are going back this Dec. with our DD 6mo. Did anyone who took their kids who were this young regret taking them or did it work out great?
They can't remember it so why not save your money and do it when they are older? I took my DS for the 1st time when he was 4 years and I feel like that was 1 year too soon! My DD went when she was 7.5 for her 1st time and she still believed in princesses and the characters and actually still does at almost 9. Last time I was there I was just flabergasted with the amount of little babies and tiny toddlers. Is it because the parents want to go and can't bear to leave the kids at home? Wouldn't it be MUCH more fun without having to worry about diapers, formula/nursing, and all the other things that go with babies? And major meltdowns with 1 year olds and older?