Good for you! I wasn't near a self-aware or mature when I was your age. If I had been then maybe I wouldn't have wasted a fair part of 20 years making a mess of things!
I have the same fear of not quite hitting rock bottom - no DUI yet for me - but almost bottom was pretty damn ugly and scary so I'm optimistic that I won't have to take it any farther.
Be strong and be proud of yourself!