Well if you mean the actual law, the age of consent is 16.
And you can TRY to 'make' her wait til she's older, but why not embrace and guide and parent that part of her life, same way you potty trained, sent her to school? Why not use it as a bonding tool? You have a LOT in common on this subject, on account of your both FEMALES who like MALES.
Why not get to know her boyfriend. Have him over, engage him, bring him into your family so he has a greater sense of responsibility towards his relationship with your daughter than just the two of them.
Enjoy her!
:)
(btw, I googled 'age of consent in Kentucky', it came up 16)