I am Active Duty military and have been an Alaskan resident since 2012, i have since moved(in 2017) to Louisiana. I am asked when i became an Alaska Resident but i cant input a date earlier than

Since you are active military your state of residence is your Home of Record or State of Legal Residence. 

In the My Info section you should select Alaska as your state of residence.  You indicate that you did Not live in any other states and if your military pay is your only income you indicate you did Not make money in any other states.