Meredith Heijl, 20-year-old student from Boston was so excited to see them pass, she broke her green flip flop trying to take Pierce’s picture.

“That was the highlight of my year,” she joked, even though he didn’t wave in her direction.

Many adults at the parade were struck by the youth of the crowd.

“I think the Celtics have a new following that’s more the early 20s crowd,” said Alan Sprinsky, 55, of Braintree, who surveyed the scene from a lawn chair in front of the St. Paul’s Cathedral on Tremont Street. “I bet there’s not too many kids in school today.”

The weather helped the turnout that was 20 to 30 people deep at spots. The Red Sox celebrated in November and the Patriots in February, but the Celtics parade took place under sunny, late-spring skies that allowed the crowd to leave the winter coats at home and come out in shorts and T-shirts.

Before the rally, Celtics managing partner Irv Grousbeck unfurled a 2008 championship banner, a replica of the one that will hang from the rafters. “The first of several, we hope,” he said in a Garden hallway. Rivers commissioned the new banners for owners and players.

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Co-owner Wyc Grousbeck, Irv’s son, got a congratulatory call from President Bush on Wednesday. On Thursday, the younger Grousbeck thanked fans.

“I would say you guys made it happen,” he said. “There was no way the Lakers could win when they stepped on the floor in Game 6 with the electricity in the building. I know who won the game, and it was actually the fans.”

And a bunch of cigar-puffing, trophy-toting athletes who took one last journey together before a new banner is hung next to the other 16.