Can I teach myself piano?

Do you think i could teach myself the piano? I have played the Viola for 6 years violin for 2 and the cello for 1 so i have alot of the musical theory stuff down and my friend who plays the piano can help me. She's not amazing but she took lessons for a long time. So do you think i could learn it correctly or do you really need a teacher. I'm not really playing to become great I just want to be able to play as a hobby. Also what level would you say this book is a href="http://www.pianospot.com/1711446.html" rel="nofollow"http://www.pianospot.com/1711446.html/a if you had to guess