You can so totally teach yourself to play the piano !! I taught myself how to play the piano and violin and then as I got better took lessons. I took all the music theory electives etc in school have semi perfect pitch and I don't really think that comes in to play until much later in the game. I guess pitch helps with the violin and other string instruments where notes are variable. My suggestion would be get a good Children's beginnner piano book - it will have simple lessons to learn the notes and how to use your fingers on the keyboard. Then as you progress there are some adult beginner books. One of the first "pieces" you learn in lessons is Fur Elise. If you want to play Cannon in D you will want to practice memorizing pieces and playing them. This is where having another ear in the room comes in handy - to make sure you hit all the notes. Personally I cannot play "busy" pieces like that with music in front of me b/c I inevitably look at the wrong measure and mess myself up.
Oh and you have to count....as annoying as it is as you progress you may want to purchase a metronome to keep you on beat.
Best of Luck - can't wait to see you on UTube !!