No, 5 is definitely not too old. My Dds were 3 1/2 and 5 1/2 on our last trip, and they stayed in the (double rental) stroller the entire time without complaint. AND, neither one had ridden in a stroller since they were 2. I am praying that they will go in one again, they will be 7 and 5 this time. It isn't a matter of your child being able to walk, adults can just walk much faster than kids. I would rather bring them along at my pace than have to slow myself down to theirs. Plus (and this is a big plus), you always know where they are. There is so much that you want to look at at the parks, you can't possibly keep your eyes on them 24/7. Here's a tip: Don't call it a stroller. I told my girls as we entered the first park the first day that, as they were guests of honor, they got to ride in the "carriage". Throughout the entire trip we continued to call it the carriage, and so did they!