After my DD was born, I had 2 nodules that were biopsied. One was fine, but the other was cancer. I had my thyroid removed when she was 8M old and have been on synthroid since. My TSH levels were completely fine during pregnancy, but after she was born, my levels skyrocketed and that was their first signal that something was wrong. My Endo told me that I eventually would have gotten cancer, but pregnancy hormones caused it to appear faster.
While pregnant with my DS and now this one, I have my levels checked every 4 weeks and adjust my meds accordingly.
Personally, if they wanted to do another biopsy, I would find out why they want to wait 2 months (is it scheduling or is it because they want to see if it grows/changes or some other reason). I'd get it done sooner if you can.