Modeling of most types tends to favor the young, though there are jobs for women who look older, especially in commercial and catalog work. For most jobs, age can be important and typically agencies don’t take on a lot of models that are in their mid twenties to older, unless they already have successful careers. This shouldn’t discourage you, since there is movement to represent more diverse people in advertisement. If you don’t fit ideal model size, age, or height, you still may find work.