The short answer is no you will not be able to build your own Earthship once you finish the Academy.  However, this really depends on your skill level going into the Academy.  There are many components that go into the construction of an Earthship including plumbing, electrical, carpentry, masonry, etc.  You will learn the basics of all of these, but you will likely want to hire a professional for many aspects of the construction of your own Earthship.