If you’ve been through it before, at least you know what to expect. I commend you for taking these steps, and I wouldn’t want to say anything that could de-motivate you—but I also want to be honest about the danger.
This should be a medical detox (most of these 3-day detoxes are, from what I understand). If it isn’t, if it’s cold turkey, I would absolutely advise against that.
You should be prescribed a slow acting benzodiazepine, like Librium for example, on a taper schedule. That taper should go 10 days or so. If it was only 3 days, I’d find that very concerning.
Finally, the big thing to watch is that 3 days is not enough to fully detox, or build new habits. There’s a risk in drinking again and if you’re on a benzo taper, mixing those two is bad news.
Be careful, be committed, work hard, and feel free to drop me a PM if you’re having a hard time.