The Month of Decemeber

Starting December 1st, I began working in the Kindergarten age home. The house family, a couple with their 3 children, is from the states. I really thought this would be a wonderful experience to work with kids the age I'm used to teaching but in this setting. The family went to the states for Christmas so another couple and I moved in the house to take over. The wife of the new temporary house parents is 4 months pregnant so anytime they go to a doctor's appointment or she isn't feeling well I am in-charge.
I surely had my struggles while in the baby house but I have been in a battle every day in this house.  The thing about me is that I typically have strong opinions in general, but when you throw taking care of children into the mix I typically have research to back up my professional opinion. I understand this isn't my house, the difficulties of filling in for the parents, working with the culture of the locals, and compromise. That hasn't been my problem.
There are several frustrations going on but I only feel comfortable talking about one. A big problem is with the 2 youth helpers we have each day. They are blatantly defiant and refuse to help me. I talked to one of them early on when I notices she wanted to verbally fight with me about anything I said (come outside and watch the kids, make drinks for the kids). We didn't come to good resolve at the end of our conversation. I have talked to some other adults on campus and she is known for this type of behavior.
This youth loves the temporary house parents so luckily they aren't haven't a battle with her. Unfortunately for her, I am in-charge a lot. My prayer is that the Lord softens her heart. I feel I am just an easy target for her anger not the cause of more frustration for her. I have been very careful to keep my emotions in check when dealing with her. It is easy to get fired up with a defiant teenager. I know the importance of showing love, kindness, correction, and if it comes to it discipline.
To be honest, everyday I have needed to do a bible study and pray before I start my day. During my break, I do it again. This trial for me has been very difficult and frustrating because my relationship with this youth hinders me from working with the kids in the house. They have their own needs and issues. Thanks for your prayers.