Most probably hormones. They are just coming into themselves. After raising three girls myself the best thing I learned is to back off as soon as you notice their being testy. Once you have time, my favorite thing to do was to make tea and have snacks (Tea Time if you will,lol) and revisit the situation in a calmer atmosphere. You’d be surprised by what you may learn and how close it will actually bring you. Separating them to have one on one time with each is also really good to. Go out for a walk,a snack,a quick meal. Something where you have their undivided attention and vice versa. It really helps. Good Luck!!
No luck with girls here, but have raised and continue to raise seven sons. I think they all go through this stage when they enter the teen-tween years. Enjoy it while it lasts, and give everyone a bit of a wider berth for now.