Is my girlfriend is pregnant ?

In June 21 to 26 was my girlfriend last periods and it's been more then 12 days late we had a protected relationship and I did not even cum while we had sex so I'll ejuclated by myself whenever I feel to end we have done 4 times a same and 1 time we had unprotected I didn't went deeper because I has phimosis when ever I try go deeper my skin got itching and pain and that time also I ejculated by myself but she has irregular periods in this year January and April has been skipped and we are really scared because we are teenagers but she had no symptoms though and I really worried about this can anyone help with this??