The Segway is easy to master...2 in our party of 4 were over 65, and 2 of us were creeping up close to 80, so we can't say that there is an age limit. If you can stand comfortably for an extended period, you can Segway.
Jacob, our very competent, personable, and knowledgeable guide had us up and running in no time. His relaxed banter, based upon having grown up in St. Pete, filled in many facts about the local history, as well as the flora and fauna. It was a pleasure to have him as our guide. The tour was a definite win, even though the temperature never got over 63º.