Kittens are really really active and do best in pairs. If you have a small apartment, get an adult cat over 18 months old. By that time they reveal their true personalities, and you can get one that is more on the sedate to lazy side. Even in an apartment, you really need a sturdy piece of cat furniture in front of a sunny window, and it needs at least one sisal wrapped post. If you can't put it in front of a window, make a nice bed on top of a dresser in front of a window. But back to your question - this time of year, shelters are overloaded with kittens. They get adopted - the adults do not. A young adult would be absolutely perfect for apartment life. And you will likely be saving a life.