Hi, I am 22 year old and my gf is 20, We both had sex for first time without condom as I broke her virginity on 7th Jan 18 and i am pretty sure that I did not cum (sperm), we had hardly 1 min penetration. Here the concern is she had periods last month December 1st 2017 itself but this month from jan 1st to till now she din get periods. I am worried please help me out. It was unprotected sex although I protected by not releasing semen, so is that her period getting delayed like irregular periods or its the symptoms of pregnancy?