My first coaster was the River King Mine Train at SFStL, and I was 5 years old.  I really loved that ride.  I moved onto bigger and better things a couple of years later though, when I first rode the Screamin' Eagle at SFStL.   But that ride kind of scared me, so I didn't really ride again until 1997, when I rode the Raven, at Holiday World.  That's the coaster that got me hooked, in case ya didn't see my name. ;) 
 
-Raven_Rider