Is it ok to for me to drink one cup of coffee a day while I am pregnant.?

Moderation. Nothing has ever shown a moderate amount of caffeine is harmful. Don't overdo anything, and you should be fine. However, no amount of alcohol or smoking is considered safe....
One cup is OK. One cup of coffee per day while pregnant is acceptable, assuming no other sources of caffeine.
Maybe not. Most would say ok but as we learn more bat metabolism and fertility, the more we respect caffeine as a bad actor. I think it should be strictly avoided. Your baby only has one shot at pregnancy and fetal development.