Starting my own business - how to actually make a profit?

Okay so I wanted to start with dog beds (for small dogs) then eventually tees dresses and bows.. I'm 15 so I can work max 20 hours a week if that.. I would be making the beds and clothes myself.. Unless is there a place I can buy them wholesale? If so where? Are there any laws I need to know about? Now that I think of it re-selling sounds better.. Should I make it an LLC? Are there any websites that will walk me through this?