In fairness to sonly there are some seriously misguided posts on here, I have to say I agree with sonly
For some reason this thread is just packed full of posts encouraging 14 year olds to have sex! Some girls are academic and not interested, some are sports mad and devoted to their sport. Others are knitters, crafters, shy, happy to be single.
The narrative that every girl at 14 is wanting or involved sexually is misguided and totally wrong. Maybe that is YOUR experience pardon but you certainly can not speak for everyone!! 
Surely at this age it is about emerging independence, adventure and finding themselves. Not latching onto boys and under age sex!
I had at least nine girls in my group, and none had sex before sixteen and many waited until they were ready at eighteen or beyond.
I encourage my son to take care of his body, have self respect and be discerning. I will say the same to my dd. Having standards and self respect is not a bloody negative!
So op, tell your dd to take her time. If he is older he could be prosecuted. Be aware that the age of consent is there for a reason.
Keep lines of communication wide open. No judgement. Encourage self respect and self care over sexual activity.