I can add to what others have suggested. I started with the Alfred Adult All-In-One Course Level 1 (lesson, theory, technic), a hard copy book, not on-line. My goal was to get a teacher if I made it through the book. When I finished the book, I started looking for a teacher and bought the Level 2 book in the meantime. After a false start with a first teacher, I found a second teacher that I connected with and we started with where I was in the Level 2 book.
I started getting bored, and was looking at the second movement of Mozart's sonata in C for piano (K545), and realized, hey, I can probably play this. The next time my teacher came for a lesson, I played the beginning of the movement for him, and never went back to the lesson book again.
I do recommend the Alfred books for adults, but I echo the other recommendations to get a teacher.
Also, watching other great pianists can be just as instructive. I went to a George Winston performance and had a good view of his hands on the keyboard. All of a sudden, advice that my teacher had been giving me for the longest time all of a sudden made sense. So now I count George Winston as one of my teachers, and Jon Kimura-Parker, and Victor Borge, and Christopher O'Riley (God, that guy's an animal on the keyboard. Last Sunday he played one set straight through for about and hour and 20 minutes with ornamentation I cannot even imagine playing myself, taking little more than a few seconds between pieces. He "talks" the music he's is playing too, you can't hear him, but like reading lips I could tell he was actually whispering what he was playing).