Well, nothing beats training someone to be good at something or a business he or she knows nothing about initially. So, if it's possible to train the teenager in the line of the company's business, I really don't see why it's going to be a hard task for him to take care of.Well it is not an easy task to manage a business.
But there are many business that a teenager can handle and handle it perfectly but if the business is big one he/she won't be able to handle because some business needs experience to be successful.