My February blocks are not 12 1/2 inches. They are only 12 inches square. I measured as the instructions said. I don't know what i did wrong.
Mine are coming out fractionally smaller - around 12 1/4 inches. I believe Amy responded on the main boards that this could be due to your seam allowance being minutely off. I am just going to keep going and perhaps cut all blocks down to 12 1/4 or smaller at the end.