You have to be 25 to take any vehicle that's considered "premium", such as a sports car (Camaro/Challenger/Mustang), luxury, or even premium, or a premium SUV. If you're under 25, there's an upcharge for underage renting, and you have to have a good driving record. They most likely won't give you anything above a full-size (Malibu/200/Fusion/etc.).