A basking island is important for aquatic turtles. If an aquatic turtle can not dry off, they may develop a fungal infection of the shell. Should your turtle develop such an infection, pet stores carry effective treatments that can be easily applied. Taking on a turtle as a permanent pet can be a very long term proposition. Samantha is thirty and probably has many more years to go.
Turtles live a long time so be prepared for the commitment.
Turtles have also been known to carry salmonella. The water that a turtle lives in can be a breeding ground for disease so it is important to keep it clean. I always insist that children wash their hands thoroughly after handling any animal as a safety precaution. Lizards I have had less satisfactory experiences with lizards in the classroom. Iguanas are often sold in stores, but are generally not appropriate.