Can I get pregnant by having lovemaking only once?
Yes, a girl can get pregnant if she has only had lovemaking once.
It depends on the the menstrual cycle. If there is a ripe
egg released from the ovaries of the girl, ready to be
fertilised and that same day the girl has sex with a man,
she can get pregnant.
This also applies, if she is having lovemaking for the first time in her life.