If you're going to see a show about a guy freaked out by his 30th birthday, like Jonathan Larson's ''Tick, Tick...Boom!,'' the first thing you're going to do is compare ages. That's true no matter how good the production is, and the Westport Country Playhouse's is an elegant one.

So whether your 30th birthday coincided with disco fever, the Monica Lewinsky scandal or V-J Day, you're likely to want to slug the lead character, Jon (Colin Hanlon), who at 29 is tortured and panicked because his youth is over and time is running out for him to do anything important. The ticking referred to in the title is the ultimate biological clock, the one that eventually goes: Boom -- you're dead. But it turns out that Mr. Larson, whose alter ego is Jon, was not a clueless kid worrying about his mortality when he had his whole adult life ahead of him. He died at 35. And to appreciate ''Tick, Tick...Boom!'' fully, we should keep his real-life story in mind.

Mr. Larson, who grew up in White Plains, originally wrote and performed the play as a monologue in 1990 and dedicated it to a gay friend who was H.I.V. positive. Then he wrote a full-fledged...