Unlike what many people think, poor appetite in young children is not inborn; instead, it has more to do with the surrounding environment. Therefore watch out for any sudden lack of interest in food in your child as it could be a manifestation of a struggle they are undergoing.
In life, you have lots of different challenges. Some will be in regards to your personal life, some will be recreational, and plenty will be to do with your job. You will learn so much over the course of your years on this planet, and the experiences you gather will be so valuable.