Hi Swift,
Can you postphone to this year, ha-ha, just kidding.
Go ahead, and enjoy being a mother.
For Bazi or astrology in chinese metaphysics, the chart consists of four heavenly stems and four earthly branchs which come from the twelve animals signs. Even if your child is born this year of the Ox, there are still three more pillar of the month, day and hour. And each is assign an animal sign so even if the year is an ox. you could get another two tigers from the month and the year, then how?
The saying:"一山不能藏二虎“ has nothing to do with astrology readings. It more refer to a situation where with two dominant and capable persons, one of them have to find another greener pasture as both want to have control of the situation. Of course, the chinese meanings covers a wider scope.
Till-then, cheers.
