I am in the same situation. I am 5 months pregnant (a boy!)and stationed overseas in S. Korea.
No, it is not too late to take the chapter. You can chose to take the chapter 8 any time up until 30 days prior to your due date.
Usually, any chapters take a maximum of 14 business days.
I was told that if you take the chapter, since you become a civilian, you can fly after your no-flight date. But on that I'm not quite 100% sure, you should ask your commander, or possibly your doctor.
But most importently, congrats on the baby! I wish you luck on getting your chapter and I hope everything works out for you!