Raider, one thing I was warned about before I left for rehab for a month was not to make those weeks before I left my last hurrah. I guess this is not uncommon, and my doctors seemed very concerned about it. I was also using prescription meds, so I was told not to change anything before I left. Talk to your doctor, but please be aware that having a date can be a bit of a trigger for us...
Rehab is a gift. I am 48 and it gave me the clean break I needed. I went across the country and I went for 30 days. It is a commitment, in a lot of ways, which helped emphasize for me the seriousness of what I was dealing with. I also realized how many people don't get the help they need. Being in a safe environment (and yes you will have quite a few stories when you get out) with other people who are there to get well and having the ability to focus just on yourself is a great way to get started.
i was surprised too to find that some people were coming back for 2nd or 3rd visits, but I was there for myself. It becomes pretty evident early on who is there to goof around and who is there to get better. Stick with the winners....you are one yourself!