it depends on how many days are your cycles. we typically ovulate at the middle of our cycles. if you have a 28 days cycle, you should be ovulating ard day 14, and since sperm can survive in a healthy woman's uterus for up to 5 days, chances of you getting pregnant on day 12 is way higher than day 7. best is you track your ovulation using a test strip for a few cycles first to confirm your ovulation day.
heard of a case where the lady found out that she only ovulate only at the last week of her cycle when she did the test strips.