What you're experiencing is perfectly normal. I have heard of luteal phases being up to 18 days long.. some women ovulate on day 8 or 9.
As for the true day one, my doctor, and all of my girl books say the first day of flow, and not spotting.
I know my period has changed over the years, it was on 2 weeks off 2 weeks for quite awhile till I went on the pill, then it got shorter and I was exactly 28 days, almost to the hour it seemed like! I got off of the pill for awhile it really messed my cycle up too, and unless I'm on the pill I have a period anywhere from 21 to 25 days, ovulation can vary I think. Your body changes, at least mine did and my period is no exception. You should still have no problem conceiving, just start a little earlier. I read once that you should start on cd9 and continue every other day till the end of your cycle. I guess all of my pregnancies have caught me off guard and I never got to try the theory, but seems to make sense.
ovualation can occur any time during your cycle. it can change every month. i think i O earlier than the 14 days prior to af. this last cycle i O'd what seemed like 2 time, symptoms started then stopped then came back a week later. its possible to not O every single month as well. my af was a dependable 35 day cycle. since my mc in may, it has changed to a 32 day cycle. the first day of your cycle is the day you have a flow, or more than just a spot when wiping. if you want to find exactly when you O the best way is to either do your bbt. or use an OPK. its normal to have some cycles that are shorter, or longer. many things can change our bodies normal cycle, stress, diet, exercise, ect. hope this helps.
Yes, perkitty, I should also have mentioned that I've also had cycles where it seemed clearly like I had ovulated twice; complete symptoms once then full symptoms again up to four or five days later, very distinctive.
Thanks everyone for your answers, they all make a lot of sense; particularly thanks for the comment about the luteal phase sometimes being longer--that was specifically the info I was looking for. I think I clearly have a slightly longer luteal phase of about 16 days, rather than 14.