Good luck TTCing. I hope it's short for you.

CD1 is the first day of AF, so you would be CD17. Ovulation can occur at any time, depending on the woman. The average is considered to be CD14, with a luteal phase of 14 days. In my case, O can be between CD12-17 with a 10-12 LP.

I recommend you joining Fertility Friend and doing the charting course. Alternatively, Francesca Naish has a great book on fertility. It explains charting as well as ways to optimise your health for fertility. Some basic things you can do now is learn about different types of cervical mucus (CM) and when yours changes. If you haven't already, buy a good digital basal body temperature thermometer which measures to 2 decimal places.

I also recommend getting some basic pre-conception blood tests done. These check your iron, Vitamin d and other levels as well as looking at your rubella vax status. Also check your exposure to CMV and parvo virus. If you want to be extra vigilant, you can get tested for thrombophilia or other conditions that can cause miscarriages or problems conceiving. Also organise health insurance, if you want to go private. A pre-conception meeting with a good OB or IM can be invaluable.