"The girls like to eat vegetables."
Translation:Les filles aiment manger des légumes.
Pretty interesting question you've got here. From my point of vue, "fille" alone would rather refer to children. If you want to refer to a teenage girl (or older), you'd probably want to use "jeune fille" because the teenage girl could be offended by you using and infantilizing word.
If the girl can be considered an adult (like if she's around 20 or older), you'd rather want to use "jeune femme".
You could also use "Mademoiselle" or "Demoiselle" instead of "jeune femme" in a formal context, but as those words refer to the marital status of the woman, some consider them to be sexist.
Hope I'm clear enough