Playing songs you know at first can be harmful. You'll learn to rely on your ear and not what you see on the page.
After a year or so after good habits are built, go for it.
[your siggy is rather creepy...]
anyway, i'll have to disagree with you on that one, b/c i HAVE to be familiar with a song in order to learn it more easily. but someone did say that if you listen to a person's music a lot, when it comes to composing something yourself, you're more likely to PLAY like that person.
but Ordinary Day is gonna be the first song i learn when i get Van's songbook. then i'ma move one to the harder stuff.
but the first song i 'officially' learned is Alicia Keys' 'If I Ain't Got You', and i'm currently learning it. it's not the easiest song to learn, but i have the beggining and ending down pretty good.
but then again, you sometimes have to get accustomed to playing some of the stuff by ear, [like the afformetioned song] b/c the sheet music doesn't always have it like the song is really played, [in terms of what's missing] which is a bittersweet thing, b/c it's frustrating, but gives you the opportunity to put you creativity to good use by putting your riffs in it.