Hey! Turtles actually make great pets. Just know they can live a LOOOOONG time. 25-30 years on average in captivity. We just had one pass away at the Center who was 24 years old. We had to call her owner who was devastated- she'd had that turtle since she was 2 years old!!
Care is pretty simple. We actually keep our turtles outdoors. They are in a 5 foot by 5 foot enclosure with high walls (they can climb!), a heated igloo, and a log to hide under. They get fed fresh salad every day (lettuce, tomatoes, etc.) and that's their diet. They're pretty hardy but you'll still want to have an exotics vet who can treat them in case there's an issue. They are prone to getting cancer and have eye issues.
You can also keep a turtle in a large aquarium. Just give them dirt so they can dig and bury themselves- they do hibernate in the winter!!! They also carry salmonella so make sure you wash your hands after handling them.
Btw, all this info was for a box turtle. If you want a red ear slider you'll obviously want to keep it in a pool. They spend very little time on land and do not hibernate. They also get a bit larger then a box turtle and, in my experience, are nasty little fellas! I almost got bit by once and that was the last time I ever handled it! The box turtles, however, are extremely docile and sweet.