Can i get pregnant and what are my chances is it is the first day of my period, and my fiance ejaculates in me?

Fertility timing: The first day of your period is counted as day 1. Most fertile time to get pregnant is usually between days 12-14 (assuming periods are regular and about 28 days apart) getting pregnant on day 1 would be unusual. Sperm can travel pretty far but do best in a warm moist environment. Deposited in the vagina , they can make it up to an egg coming down a fallopian tube. Sperm outside the body struggle.