What type of eyeglasses are good for a girl with a round face?

Good prescription. The first consideration is that the power of the glasses are correct. An ophthalmologist can take care of that detail. The rest has to do with your image - what occupation you hold? Whether you want to look stylish or professional. Discuss this with your optician who can show you a variety of frames and decide after you look in the mirror which is suitable.
Avoid round frames. In general, you would want to avoid a round frame, as it will accentuate the round shape of your face.