The word you’re looking for is “woman,” son. Or “girl,” if applicable. Okay? If you can’t immediately see the difference between “a woman/girl” and “a female,” maybe you’ll notice that you don’t generally refer to a black person as “a black” unless you are someone’s deeply embarrassing 93-year-old grandparent.
Did you wince a little just reading that last sentence? Good! I’ll tell you why. It’s because the words “black” and “female” are adjectives. When you take an adjective that describes only one characteristic of a person’s appearance, biology, history, or philosophy and then turn it into a noun (like we did above), you’re reducing the whole person to that one trait. Nobody likes that. Don’t be a jerk.