Of course you will and should be junior, seniority wise to a 0 time cadet who joined a week before you.
Iīm sorry to insist but I honestly canīt see how it would be so obvious that someone who is totally released to operate the aeroplane, should be less senior to a guy (or girl), whoīs only allowed to actually sit on a pilotīs seat above 20000 feet and has got less bars on his/her shoulders... doesnīt seem to make much sense at all, does it now?