Those are the consequences

Depression, girls and alcohol
Teenage girls experience depression 50% more than teenage boys, regardless of alcohol consumption. Twelve to sixteen year old girls who are current drinkers are four times more likely than their non-drinking peers to suffer depression. Moreover, adolescent girls who are heavy drinkers are more likely than boys to say they drink to escape problems or because of frustration and anger. Severe cases of depression can lead to suicide.

Girls can be more susceptible to alcohol poisoning.
Because of lower average weight and other factors, females of all ages tend to be more susceptible to alcohol poisoning and can reach life-threatening levels of intoxication faster than males of the same age. Females have less body water than males. Therefore, if a female and a male of the same size and weight drink the same amount of alcohol, the female will tend to have a HIGHER concentration of alcohol in her blood. Moms should tell their daughters about these dangers, and remind them that these important gender differences critically impact teenage girls exposed to alcohol in the same ways as older women, if not more so.

Impaired judgement can place young women’s physical safety and sexual health at risk.
Teenage girls who are heavy drinkers are five times more likely than non-drinking girls to engage in sexual intercourse and a third less likely to use condoms, which can result in pregnancy and sexually transmitted diseases. Additionally impaired judgment and reduced coordination resulting from intoxication may lead to other physical harm resulting from falls or physical altercations.

Underage consumption is associated with higher rates of alcohol dependency.
Children who begin drinking before the age of 15 are four times more likely to become alcohol dependent as adults when compared with those who begin at 21.

Alcohol can be even more dangerous for young girls with body image or weight concerns.
Many teenage girls have concerns about their body image and experience weight management problems. For young girls who may not eat properly or who have a low daily caloric intake, drinking alcohol can place them at a higher risk of intoxication and, in extreme cases, of alcohol poisoning which can cause death.