I need advice... 10 points for best answer?

Im 13 years old and on diet. Last week I decided to order some pizza because I havent eating pizza in a month. Today( week later) I just came back for school and there wasnt anythong good to eat so Im start thinking of pizza:\ Im doing weight loss exercises 4-5 times a week. Should I order small 10'' pizza and some boneless chicken? Im definetly not going to eat everything...