This one question is actually two.
First, ever been on a TYPE's maiden flight? Example: BA 777 flight from London to D.C., 6/95.
Second, any single aircraft's first flight after delivery to an airline? Example: Yesterday, first flight of first 717 delivered to TWA, STL-DFW.
Closest I came was a 2 week old MD-83 on TWA in July. Smelled new. Cool.