Who all has noticed that when the answers are just for work you usually only get 5-10 pts. but when its personal like "How do you eat cake?" you get like 50?

Ihave a really high metabolism and only weigh 70 pounds (13 almost 14). people always ask me two questions: do you ever eat and how do you eat so much and stay so skinny.i am worried that a high metabolism wont me forever. what are some safe steps i can take to maintain being fit. (also, i already work out i am a dacer so i get cardio a lot)