14 year old daughter has missed her period 3 times, has never had sex but maybe she has because she been drunk with boye and can't remember anything?

Anovulation. Many teens do not ovulate every month and many have missed periods. This is not in any way unusual. Other reasons for missed periods in young females is extreme dieting, extreme exercise, obesity, birth control, stress, etc. In my state allowing a pre-teen to be drinking would necessitate a call to child protective services. I am sure you are not allowing this to happen, but I am very worried.