If you want to kid her next spring I would not milk her at all, reduce her food a bit (depending on what she gets at the moment and how well she is grown) and just check the udder regularly for any signs of hardness, heat or redness (which would indicate mastitis). It is unlikely that will develop, as small udders are quite normal for goatlings.
From your message it sounds that you don't have any other goats - just the goatling and the male?
Normally you wouldn't keep goats in mating pairs, only a few people keep billies (larger herds), as the actual mating is over in a flash and he is no longer needed.... I don't know where you got the advice to get a billy for one female, but I think that is a mistake. He will need to be fed all through winter and be incredibly stinky. he really should live with a (castrated) male as companion, away from the girls (plural as well). You might want to re-think your goatkeeping strategy.
You only introduce the male when the female is actually in season, usually in October/November time. Having him with the female now may well trigger her into coming into season quite early, and kids born in December are usually quite hard work.