It is not abnormal or excessive unless it is deliberately done in public places after age five or six, when most children learn discretion and masturbate only in private.
They often continue to masturbate simply because it feels good.
Some sex therapists believe that girls who do not masturbate miss an important step in their sexual development, since masturbation provides an opportunity to learn how one's body responds to erotic stimulation.
Many sex therapists believe that to have better sexual experiences with a partner, an individual needs to learn to masturbate first since it is the best way to learn what one likes and does not like in his or her sex acts.
Females most commonly masturbate by stroking or rubbing the vulva, especially the clitoris, with hands and fingers until orgasm is reached.