The hoopla surrounding Fenway’s 100th anniversary starts very early Friday, with the gang from MSNBC’s “Morning Joe’’ - Joe Scarborough, Mika Brzezinski, and Willie Geist - broadcasting live from the ballpark. (We’re told the trio of talking heads will be joined by Senator Scott Brown as well as his likely Democratic opponent, Elizabeth Warren, Senator John Kerry, MLB Commissioner Bud Selig, Hizzoner Tom Menino, and historian Doris Kearns Goodwin.) The day’s pomp and circumstance holds special significance for Tom Fitzgerald, the eldest grandchild of John Francis “Honey Fitz’’ Fitzgerald, the former Boston mayor who threw out the first pitch at Fenway 100 years ago. (He’ll be one of about 30 Fitzgeralds at the fete.) “It was great to be asked back,’’ said Fitzgerald, 77, a retired educator who grew up in Dorchester. I have no idea what we’re going to do. This is kind of like school: I’m going to show up and do what I’m told.’’ Fitzgerald, who wrote a book about “Honey Fitz’’ called “Grandpa Stories,’’ has many fond memories of his grandfather. “There was a debate about which grandchild he liked best, and the answer was: Whoever he was with. He made you feel so special.’’ One bit of advice for folks going to the game: Get there early. Pregame festivities start promptly at 2 p.m., and there will be a mass toast - with grape juice - to Fenway Park.