I've been thinking about going back to school for my bachelor's degree, and undergrad academic degree which takes 3-7 years.
That's exciting!  What kind of degree could you get?
There are so many options!  The bachelor's degree is the most common undergraduate degree.
What kind of pre-requisites do you need?  
That really depends on what you want to do.  For instance, if you want to go to a medical school for a degree for physicians, you could do science based courses.