I like what you found out a lot more than what I found. I kept finding articles that were saying 35 days at the longest. I think I'll go to the doctor anyway just to make sure everything checks out.
I would think if you are getting a period every month and they are between 36-37 days, then that is regular, not irregular. PCOS has many symptoms. RE thought I had it because I have elevated insulin, but come to find out I don't. With PCOS, you have irregular periods (meaning, months without one), weight gain, extra hair growth, etc. Usually, with PCOS, your ovaries are lined with little cysts that look like pearls. Also, you have elevated insulin levels. Google PCOS and see what you find. Not a lot of people check in on the PCOS forum here, but you might want to try posting there to see if anyone stops in.
here is what i found and it DOES NOT mention ovarian cysts
***A woman’s menstrual cycle is highly individual, and can range anywhere from 24–37 days. What’s “normal” is what’s normal for you. The length of your cycle may be affected by many things, including illness, stress, travel, fertility medication, and close association with other women. At different times in your life, your menstrual cycle may become irregular due to a variety of factors, including pregnancy, stress, diet, hormonal imbalance, exercise, and illness. (For more information, again, refer to our article on irregular periods.)***i got this off of womentowomen.com
so if you're cycles have been this long after stopping birth control, it is very likely, that this has become your "new" cycle....i have 2 friends with PCOS, and they have SEVERE cramping, and can sometimes feel the cysts "burst".....and it causes them to MISS periods for several months, or bleed nonstop for several weeks.....i do know there are a few women on the forum who have PCOS, and they'd have alot better answers for you....but when i just typed in "cause for 35 day menstrual cycle" the above quote is what i got and alot more like it, none of them mentioned PCOS