Last time I only had 0-3, it was a bit big at first, but she grew into them incredibly fast, and I just rolled up the sleeves a bit. It really didn't seem like a big deal.
This time, I may pick up some newborn size, but only if I see it incredibly cheap at the sales or 2nd hand or if I can borrow from someone. Otherwise, not gonna bother.
Girls tend to be smaller. OH was almost 5 kg at birth, and I was 3 kg, DD turned out to be 3,5 kg, but was only 50 cms long. My friend's daughter was also 3.5, but 56 cm long. There's just no way to tell in advance.