Pregnancy Concerns: Late Period & Potential Conception After Intercourse

Question
i am 14years old.first day of my last manstural period was february 7 and it ended on 12th of feb.most importantly that period was late as first day of my second last period was 28th of december.on 4th of feb ie 3days before my periods i had intercourse with my bf after that i never had any sex act.now i wanna ask that is there any real chance of me getting pregent,as you answered another girl and you suggested that once one get periods she can,t get pregnant,how much sure that is.please reply as i am in deep problem i can,t sleep properly due to worry of getting pregnant.i will be really obliged.

Answer
If you started your period on February 7, you are not pregnant. If you have a normal 28 day cycle (from the first day of your period until the first day of your next period) ovulation occurs around cycle day 14. You can ONLY become pregnant if you have sex on cycle day #13, 14, 15, or 16. You cannot become pregnant so close to the first day of yur period. Don't worry.