Don't worry, Amazon will ship all products unless there is something stopping them. Sometimes it might be products that are not available in their warehouse and they need to get a refill on the products, or simply something went wrong with the payment and whatnot. Sometimes it can take up to 2-3 weeks to get an item shipped, depending on the size of product or availability.
Amazon wants to make money, and they only do so if the items are shipped. Therefore, they'll do everything in their power to get as many products shipped as possible. Don't worry!
Good job on the first few sales btw!