I'd just wait and see what happens as you never know how big the baby will be (DD2 was a whole kilo heavier than DD1 at birth and now, at 2 months is the size DD1 was at 9 months so completely different) or what people might buy you as gifts (we are actually struggling to get DD2 into all of her presents). You can always dye some of DDs things for your DS too - pink can become red quite easily for example.