28 weeks pregnant is it a bad idea for me to stop eating beef.

No worries: Normal, healthy pregnant women eat different things all over the world, depending on culture, choice, food availability, etc. The one requirement is a balanced diet. Thus, if a woman already has enough protein, iron, and calories without the beef, then leaving out the beef should not cause a problem. If she needs red meat but doesn't want beef, just switch to pork, lamb, duck, or other dark meats.

No: It is fine if you want to stop eating meat.