Yes it is possible for a girl to have an Adam's apple.
Although the Adam's Apple is most common in men after they hit puberty sometimes girls can develop an Adam's Apple too.
I've known a few girls that developed Adam's Apples when they hit puberty so it is entirely possible for some girls to get an Adam's Apple.
If the girl or even boy doesn't want the Adam's Apple they can have surgery done to have the Adam's Apple removed.
Although that comes out of the persons own money because Adam's Apple Surgery is considered to be cosmetic.
The Adam's Apple is a projection at the front of the neck formed by the thyroid cartilage of the larynx, often prominent in men but girls and woman can get one too.
But it's rare that a woman or girl gets an Adam's Apple.