Soften Her Heart of Stone

So, how to discipline a teenager. I haven't really figured it out but had to do it tonight. Not sure how effective I was.......
So, we sat down for a family meeting around 8 in the evening: me, Esther, and Mary. Jackie started out with us but fell asleep. I figured she probably didn't need to be that involved since she was pretty oblivious to what was going on and just kept interrupting us as she would burst into her version of the B-I-B-L-E.
The conversation began with a question. Well, really a series of questions. What is a family? How is best to live with one another? How do we relate and be open to each other? From there we talked about choices. Mary answered a few questions. Esther just kept quiet and looked at the wall ahead of her.
Finally, I became direct and told them that I expected them to communicate in the house. I also expect them to tell the truth and to be trustworthy. Then I again explained to them that I had some Christmas things stored in one of the cabinets and some of it had been eaten. I told them that it was best to admit it now and just ask for forgiveness instead of making the problem bigger by lying. Still no admission. I asked both of them directly if they had taken anything.
Then I told them that I knew who had taken it and had removed it from their things. This meant that since they had hidden it, they possibly felt in their heart that it shouldn't have been eaten (sneakiness) and that they then covered it by lying.
We talked (or I talked) about how one lie will lead to another one until it is just a big mess. We talked about reputation and trustworthiness. Again, I asked. Again, both refused.
I directly told Esther that I knew she had taken it. She adamantly denied it. For about two hours we went on like this. Finally, I told her that one thing I wouldn't allow is someone that I can't trust in my house. I have another young girl that I dearly love but she's not allowed to enter my home because she steals and lies. I asked Esther if she wants to be in that category. After a few minutes she told me that she took it. But, there was still no sign of remorse. Just stoniness, like yeah, I did it. So what. The whole time never looking at me, never saying sorry.
We then talked about consequences. Her consequence is to be missing her school trip on Friday. That's when I saw remorse. The tears started. I'm not real sure yet if the remorse was for lying, for getting caught or missing the trip.......
I wish these girls could see their real potential. Esther is a beautiful girl. She's smart. She's a natural leader. I'm praying that God will soften her heart and that she'll use that potential to reach somewhere she's never dreamed or imagined reaching.
But, one thing I'm certain of is that this teen years stuff is no joke. By the time the conversation ended all of us were crying. OK, Jackie cried earlier because of wanting to sleep so by the time we were crying she was knocked out. Esther was most likely crying because of missing the trip. Mary was crying because she felt bad for her friend. I was crying because I had to be the bad guy, which I hate.