I would just keep an eye on it that it doesnt turn into mastitis but other than that I would just leave it alone...: ) however, If it gets huge, uncomfortable for her and its even sided you can test a bit of the fluid to see if its real milk or a watery version. Some does can be milked from a PU with no issues..others will empty out then not produce any more..the down side of milking is you open the orphus to bacteria..so only do if really necessary

Do not milk if she become lopsided,,, this will cause her to always be lopsided. Usually the udder is only good on one side and sickly on the other...
I would breed her as soon as she is both old enough and large enough for a real udder that Im sure will amaze you!