Very well done - and I like that you made this a project for the whole family!
I would have done it a bit differently and just put chicken wire around the sides instead of the plywood - babies like to see out and see the world around them, without feeling threatened. Having the top "open" means that any time you come near them, you're approaching them from above, which can be really scary because they innately fear predators from above. I would have put a piece of plywood on top and kept the sides uncovered albeit reinforced. Otherwise, great job!