It depends.
Transitioning is acceptance, coming out, makeup, buying clothes (think "thrift stores" at first, maybe always), therapy, hormones, and ultimately surgery(-ies).
Throw in friendships, relationships, life, cars, family...all need to be transitioned (or acquired). Education is part of life...so is money+job etc.
"Transition" can last a year, or a lifetime. It all depends on your resources and resourcefulness.
You won't be buying hormones anytime soon (it takes a few months to get them), so just regular life stuff is priority...but you can buy a few clothes and figure out what size you wear. Plus, you probably want to take your time...so I'd say a typical transition is a 5-10 year process. Go from there...
Thank you for your service, btw!