Is my girlfriend pregnant?

Patient: So this has been bothering me for a while and i really need somebody to talk to me about this. I am a 17 year old male and I am worried that my 16 year old girlfriend is pregnant. We only had vaginal sex once back in May, we were virgins at the time, and it was with a condom and I did not ejaculate. Since then, she has had a period at her regular time around the 24th in May and June, so the reason I’m concerned is because her period is now late and I’ve read about women being pregnant and not knowing because they had no symptoms and still had a period at the usual time. I don’t believe anything unusual is happening to her to make her feel or act different. I hope to get a reply soon, this is worrying me very much. Thank you.

Symptoms: Delayed period