“I am in the military and my wife has a child from a previous relationship in which she was never married and no custody agreement was every arranged and she has had her for her whole 7 years of life. They have lived with me for two years in which I have supported his child and I am on orders to go to Colorado, could we get in trouble for bringing her with us?”
You don’t say whether the girl’s father is at all involved in her life, such as spending time with her. Either way, since there is no standing court order, the best course of action would be to contact the father and see if he consents to the move, and then to open a case with the court to have the agreement formalized. He may be concerned about going to court because he will be worried about paying child support. If you are in a position to do so, you may want to offer up front that you will not seek child support – the court will push you to get support, but in most cases you can agree to a minimal amount, like $1, if you work with a mediator.
Opening the lines of communication will allow all parties to voice any concerns and hopefully come to an agreement without dragging the child into court. If he does not consent or if there are other concerns, then contact a mediator or a family law attorney to help everyone involved in the child’s life to come to an agreement.