hi doc...plz help me

i had sex with my gf on 18 april nd thn she had taken i pill within 4 hours

thn she got her periods on 22 april ( very early) bt she ws expecting ths to be on 13 may

nw its 24 may nd her periods hd nt yet started....so is there any chance she is pregnant...i m really scared as we are nt ready fr a baby...