Each pair of leaves I've observed comes up each week, it's pretty easy to keep tab at this point in how many weeks old they are. By the second month after they had sprouted, it's time to transplant them. In order to know when to transplant adenium seedlings, they have to have at least six true leaves or more for the transplanting to be a success. However sometimes the plant may go into shock and you should expect some lost unless you're lucky enough to have lost none.
