First day of your period is Cycle Day 1 (CD1).
Yep its the first day of your period
BTW, if you're going to start tracking (even just periods), I recommend an online chart site like [url:3d8qii6d]http://www.fertilityfriend.com[/url:3d8qii6d] - it'll help you get some stats on your cycle lengths, etc.
Day 14 for some, but really it's usually anytime between Days 12 and 16. Sometimes it's as late as Day 18. You can detect ovulation by charting your body basal temperature first thing in the morning. Your temperature jumps after ovulation, and by doing this, you'll soon see what pattern is usual for you.
In my case, I usually ovulate on Day 16, but have been as late as Day 18 on occasion. Your period will usually follow 12-16 days after this.
Also, you may notice that your cervical mucus (CM) becomes plentiful, clear and stretchy just before you ovulate. The best time to ttc is when you see this, you're usuallly most fertile just before you ovulate (the day before, or better still, a few hours before), and right through to a day or two after (in case the little eggy's hanging about, or you've released two!)
Best of luck.
just to let you know fertility clinics count day 1 as the first day you have red blood after 3pm. so if you start your period at 8pm, the nest day is cd1!