Bedroom Sharing for the littles?

So I have a little girl already she will be just over two when my second girl will arrive. Just wondering what you all are doing with the bedrooms? I’m planning to have the new baby sleep in our room for the first few months then move them to another room with a crib. Do I have them share a room? Just add a crib to our guest room? I really don’t need two sets of changing tables and baby gear since I can use the same for them both. My 1 1/2 yr old sleeps fantastic never wakes at night and I don’t what to mess that up.