Age 3??? Oh you poor thing. LOL!
My advice (for what it's worth):
1. Pack as light as possible. The less you take, the less you have to carry around with you all day.
2. Spend at least 3 days there. You can't see it all in just one or two.
3. SUNBLOCK & a hat! It's pretty hot in Florida right now...and don't be surprised if it rains!
4. Be prepaired to stand and walk for 90% of the day.
5. Drink plenty of water! WATER!! Soda will dehydrate you so fast, and the last place you want to be is at the Medics on your vacation.
6. Be prepared to overpay for everything. Water, food...everything. That's part of any theme park.
7. The best advice I can give you...RELAX! If you get angry about something - long lines, prices, etc - Take a deep breath and remember...."It's a small world" ..and other guests there probably feel the same!
It can be stressful to go to Disneyworld! But, it can be the best time in your life! Even if your not a kid!
Have a safe trip & Give Mickey a big hug for me!:-D
Disclaimer: My opinions are purely my own, and should not be taken with alcohol. If at any time I start to make sense, discontinue use immediately.