My gynecologist is an expert on PCOS and says that having PCOS does not necessarily mean you are going to have an irregular period. I, as well, had my periods every month, on their time (I only got them a week earlier in December when it is too cold and a week later in July when it is hot) but apart from that there was nothing to indicate PCOS apart from the weight. My previous doctor did not even consider the possibility of PCOS existing because of my regular periods despite the fact my weight sky-rocketed when my periods started when I was a kid.