I would place it under the window that is closer to the center. It will give you more room around it.

I agree with Tara another option depending on the size of your bed and headboard would be to angle the bed between in the middle of both windows. I don't how much walk space it would give you around the room but definitely the bigger wall should work. I'm too OCD for angled furniture placement but I've scene people who can make it work for their space and it's a nice look.