It's asking if I'm a Mil. Vet that was honorably discharged. What if I'm still in the military and also a Vet? Do I check the box?

If you are still active duty then select "Active Duty Military".

Please make sure that you check the active-duty military box for the W-2 on the "Do any of these uncommon situations apply to this W-2?" screen when you enter your W-2 from DFAS.