No worries. They won't ask your 4-year-old for an ID. Last time we went to WDW/SW my son was 15. Several people during the week thought he was my DH. He's a big kid about 5'10" at that time with a full beard and they asked for ID, but I explained he was only 15 and didn't have a driver's license yet and they were fine with that. Have a great time. We love Sea World and I'm sure your DD will too!