I put on eras that I would take step 2 in late Nov. But I may need to postpone it and take it in the 1st week of Dec. instead. Is this a problem since on eras I said Nov?
It's only a problem if your Step 1 is low and programs may want to use a Step 2 score to decide whether to interview or rank you. If your Step 1 is adequate, it shouldn't be a huge problem.
Nobody is going to care, if they even notice. If anybody asks, just tell them that your schedule changed and you weren't able to take it earlier. No big deal.