First day of my period is 23 of august when is the best time to conceive?

Ovulate 2wks b4 mens: Ovulation occurs 2 weeks prior to menses (which occurs if no fertilization has taken place). So if your menses are regular, plan to have sex about 2 weeks prior to next menses. In meantime, go see your family doc for preconception counseling and stat taking prenatal vitamin now. Don't wait for positive pregnancy test as neural tube defects occur early on prior to missing period.