Is a girl fertile 14 days after the day of her first period?

Yes: A woman is fertile 14 days before the first day of the next period. If she has a 28 day cycle, then that will be 14 days after the first day of her last period.

Ovulation : Yes.. You may be ovulating during mid cycle. Calculate the length of your menstrual cycle and roughly 10-14 days in the cycle you can be ovulating.

Ovulation: Ovulation usually occurs just shy of half way through a cycle. Sperm left in the vagina on any of the five days before ovulation are the sperm most likely to cause pregnancy.