Jace seems to be the oldest, which tracks. Due to their friendship, I'd bet Yara and Jon are close in age. Since kryptonian and Amazonian aging is all over the place, their ages matter less, I think.
Fox is clearly supposed to be the oldest, with Jon as the middle, and Yara as the young principled hothead. I’m honestly dying to know what exactly the Trinity dynamic is here, because there’s no way Jon and Tim have the same relationship as their predecessors.