Oldest daughter doesn't want to visit me much. Other 2 are fine. How should I handle the situation?

So my ex wife and I just (July 7th) agreed to a custody arrangement. Every other week during the summer, every other weekend, and i get them on the monday night that I dont have them for the weekend. My oldest, 15, didn't come for the first weekly visitation at all. The other 2 did and we had a good time. They missed their mom towards the end of the week but we made it through. We are on the 2nd weekly visitation now. All 3 girls came this time. The oldest came on Thursday, 1 day early. The other 2 came on Friday as scheduled. The oldest spent Friday night with a friend and came back on Saturday afternoon. All was going fine. Sunday night she asked if we could go to a trampoline park on my day off either Tuesday or Wednesday. I said we would talk about it after work on Monday. Well, I pulled in the driveway after work yesterday (around 1030am) and got a text from her saying she is ready to go home. She had just woke up. When I got inside, she just said that she misses her mom. I just don't know how to handle the situation as far as the other 2 younger girls are concerned. They miss their mom too, but I wouldn't let them go back during my time, so how is it fair to let the older one go home early?I should say that we have been separated/divorced since may 2012. We had an original custody agreement that basically said we were working it out amongst ourselves. It just never worked out.Edit: the reason for this post was to get advice on how to handle the two younger kids if I let their older sister go home while making them stay, or not making their sister come at all but making them come each time without fail via /r/Parenting http://ift.tt/2a2K1us