Remember that snakes can live very long lives and being 13 you will be going through many life changes like college and you will still have your snake to care for. Some dorms don't allow animals and many apartments have similar rules. Make sure that you only acquire what you will be able to easily handle during these changes. Many snakes end up on craigslist when they are left with parents when the kid goes of to college and the patents get tired of caring for it.

I say slow down and concentrate on the one you have. If done right you could turn that big tank into a ball python palace. The key to big tanks is providing a feeling of security to the snake by providing several hides and cover like drift wood, plants, and moss.