Eat if you're hungry.
I don't know how tall you are but you are very light and if you need to gain weight to have a healthy bmi then you should eat more.
As you are walking and doing dance you should be eating more to ensure you are eating sufficient calories for the amount of exercise you are doing.
There's nothing wrong with eating more than normal. More often than not you will go through phases of being very hungry and then not very hungry. If you are hungry do eat though