Hello Doctor, We Had Unprotected Sex On The 3 August

Hello doctor, we had unprotected sex on the 3 August and then on the 11,12,13, and 17 of the same month.it was our first time. her periods were supose to start on the 19 of the month today is 24 and she hasn't gotten them yet.. She is having cramps and stomach pain but there is no sign of her periods..
My question is
Is this normal after having sex for the first time.?
And can she be pregnant.?
What should we do now.?
Please help