Wow! The girl is pregnant, not made of glass!!

The best thing you can do for your baby is stay active while you are pregnant. It makes for an easier delivery too. You will be going through an intense physical ordeal when you birth. For any other big physical event we would be working out like crazy in preparation!
A general rule of thumb when it comes to any exercise during pregnancy is to continue at whatever activity level you were before you became pregnant. If you need to increase your activity level, do it slowly. Listening to you body is the most important thing, in any case!
I just had my last baby at age 48. I worked full time as a waitress and continued to bike until the last few weeks of the pregnancy. I have biked and stayed active throughout all 9 of my pregnancies. They were all full term, uncomplicated births. That is in large part because I stay very physically active during pregnancy. I also eat healthy and listen to my body.
I figure you have had your baby by now, flowergirl. How did it go??