Traditionally, white was worn by single women, and black by married women. It really doesn't matter today- I've seen both wear either or even another color.
Personally, I prefer black, even though I am a young single woman. My hair is dark and I really feel like I stand out too much in a white veil. I don't mind looking like an Italian widow at all, regardless of what others think. She could have a purple or striped one for all it matters.
Congratulations on your new little one!