Please seek medical and professional help first, then think about 12 step meetings. Meet with your doctor ASAP and be frank with them about your drinking; don't feel ashamed, they have heard everything and worse. Consider going on Naltrexone while quitting or tapering, it helps many alcoholics (myself included) manage the strong urge to drink, at least in the short term while you get sober. Find a therapist who lists addiction counseling as one of their specialties, meet with them weekly and be as honest as you can. Most drug and alcohol addicts are self-medicating for other mental health issues like anxiety and depression or PTSD, and none of those can be properly addressed in 12 step meetings.
Depending on how long and hard you've been drinking, you may need medical detox. I actually had a seizure while trying to quit on my own -- bad idea. I would get out your insurance card, call the number for mental health services (alcoholism is considered part of that) and tell them you think you may need inpatient detox. A nurse can assess you over the phone as to whether you need it.
Outpatient group meetings (not AA) with other addicts and alcoholics has made the biggest difference in my recovery; finally being able to talk to other people who truly understood the terrible (and sometimes funny!) daily struggles of hiding, isolating, and self-loathing was like finding out I had long lost siblings. The other thing for me was taking care of my anxiety and depression with the help of my therapist and psychiatrist-prescribed medication; it was only when I addressed those underlying issues that I was able to quit and stay sober.
Try to not get too down on yourself, you're still very young and can accomplish a lot with your life. Cheers.