It doesn't matter that you think it's ok to house two snakes together. It's really not. They get zero social fulfillment form it and it makes any issues you may have with one snake difficult to diagnose and treat because you'll never know exactly which snake has the problem.
As for advice, cross your fingers the female doesn't go through a full breeding cycle and die because she's too young. Start researching on exactly how ball pythons reproduce if you want to know what your female could possibly go through. Try googling to see if anyone has cared for and posted about a female that became gravid at a young age. If there's a chance she'll produce viable eggs, any chance at all, you might want to look a a diy incubator or buying one. If anyone has any specific data, stories or links as to what to do with an accidentally gravid young female snake, let's contribute that.