Should I buy a ''pregnancy wardrobe'' now I know I''m pregnant or should I wait?

You could start with a few items now, but it is probably best to wait and buy items as you need them so as not to waste your money. At this early stage you can''t know how big you will get, so to buy bras for example would be impractical as later on they may not fit. Often you can continue to wear your normal clothes well into the pregnancy, so it is probably best to wait.