I'm 17, how do I get financing

In the United States you generally have to be 18 years of age or older to enter into a "binding" contract legally.  This is referred to as "Legal Age".  Until the age of 18, the contract is not binding.  A minor can enter a contract at any age provided all parties agree, it is just not binding.

A conventional mortgage contract requires Legal Age.  

Age has nothing to do with credit score except that many creditors will not extend credit to a minor since they can not be bound.  As such, a minor can get a joint or co-signed account at very young ages to establish credit.  It is fairly common.

Is a joint or co-signed account possible?  If so, pursue that or simply wait until you are 18.

All this said, your enthusiasm is awesome.  Just don't go credit crazy when you turn 18.