Read the following text and answer the question.

Dion: Hi. My name's Dion.
Nita: Hi. I'm Nita.
Dion: Nice to meet you.
Nita: Nice to meet you, too.
Dion: We are in the same class. How old are you?
Nita: I'm fourteen years old.
Dion: You are a year older than me.
Nita: So, you are thirteen years old. Where do you live, Dion?
Dion: I live in Makmur Village. What's your address?
Nita: It's on Bougainvillea Street. Do you live with your family?
Dion: Yes, I do. I live with my parents, my sister, my brother. What about you?
Nita: I live with my parents. I'm the only child.
Dion: You must be lonely. You don't have friends to play with at home.

How old is the girl?