Hello Ariel,
With a name like that, you will fit in perfectly among the other Princesses at Disney World!
When my daughter was younger, my husband and I would always debate whether or not she would need a stroller. And inevitably, we would end up renting one. I rented a stroller for my then six-year-old daughter one day because I knew my family would not be able to take a much needed mid-day break. Instead of hearing her whine about achy feet, she quietly sat as we maneuvered between attractions. It was heavenly!
Since you will have both your three and six-year-old daughters, I would suggest renting a stroller from Disney. The strollers at Disney are large enough to for an older child so if your daughter needs a break, she can sit for a bit. And your toddler may want to exhibit her independence most of the day so an umbrella stroller may not be your best bet. Even if you rented a single stroller, both of your girls could make the most of it.
To see where at the Parks you can rent strollers, click
here.
Hope this helps!