Hmmm....that's interesting because my MIL (who is from PA) says circle is a girl and back and forth is a boy, so that would mean you are having a boy if you go by her. It was right with all four of mine
Does she like art? Maybe an art party using natural items to paint with?
Or maybe a harvest party? You could bob for apples. Maybe have a beanbag toss (you can make simple bean bags from felt). Things like that.