I'm sure you did the best you could. Maybe she's just a short term Colt fan because they won the SB. If the Cowboys really show they legit SB contender, maybe she will revert back to the way you raised her. Believe somewhere in the Bible it says something like, raise a child in the way he (she) should go and she will not depart from it. Keep hope alive.
BTW: I'm a Cowboy fan but my brother is a Skins' fan. He's got 3 sons: one's a Redskins fan, the others a s Cowboy fan (even tho he lives in Baltimore) & the 3rd is a baseball fan.