I don't know the american situation. BUT it sounds like you've every chance. A lot of linemen I've known and work with now are ex millitary " I'd see that as a definite PLUS ! And I got into line work ( many years ago) through knowing someone in the job. "My uncle". He got me the inital interview and put a good word in for me. As regards schools , union etc the guys on here will put ya straight. GOOD luck with it mate. An let us know how ya get on.
BE LUCKY.