Can the 15 year old be on the business license? how do we file taxes? outside of our business, how much can we make before we have to file taxes as an individual?.--Answer1:they are too young. not to rain on your parade but they need more life and work experience.. and a couple college classes to (help) ensure sucsses with owning a business.--Answer2:the 15 yr old, by state law, UNLESS court emancipated, may notsign anything with anyone. The 20yr old one can. find a biz plan template and start filling one out.visit the library and read books on small biz.take one class in same. then, open your intended biz.