And don't go listen to Heroes. Listen to The Rise and Fall of Ziggy Stardust or Aladdin Sane. And then Space Oddity and The Man Who Sold the World. Then do Low, Heroes and Lodger, in order like you should. Then listen to the rest of his catalogue 'cause it's all fucking fantastic! (even if I like Heroes the least)
Ziggy Stardust is great and all, but I think Heroes is the best starting point.