The adenium straightening out after water has been given is a very good indication that it was thirsty. Mine also get droopy when they are thirsty.
I have no idea how old this seedling might be...but seedlings are very thirsty all the time. With a potting media that is loose and well aerated (as they should be), in the current heat and with no rain, watering every other day is good for this size of seedling.
