What are the chances of getting pregnant the day of ovulation or a day later if the male ejactulated inside?

20%: At age 24 probably about 20%. That is the average pregnancy rate per month around the time of ovulation provided there is nothing in your history to suggest infertility.

15 to 20%: Intercourse prior to ovulation, if everything else is normal, gives a 15 to 20% chance of conception. Intercourse the day after ovulation gives almost no chance of conception.