Answer: The first when starting a business is knowing what the business is going to be about
Explanation: You made it clear that you want to open a physical store. But before opening a store is important for you to know some basic stuff. Your mom is right about taking some business class and while you take them you can also open the store, which is a learning proccess that never ends.
When opening a store you need to be clear how your product or services is going to help or be a way for people to entertain or enjoy. When you are clear about it you have to think about putting the store in a place that you know you are going to get good visibility. Also, you are going to work on the marketing side and you can do this online creating ads for people to go and see your store.
When you are clear about the ubication and the ways of how to make people come to your store, you need to also think about the design. The type of product that you want to sell needs to have an attractive design that catches people's eyes.