"She was beautiful," Castrilli said. "Everybody loved to sit there and watch her with her short skirt jumping around. It was great. She's very athletic, and you had to be athletic to be a cheerleader. ... And she was not only athletic, but she looked great doing it."
Streep had her share of high school boyfriends, Castrilli said -- including one who would go on to make a name of his own.
"Funny story, she went out with J. Geils from the J. Geils Band," said Castrilli. "He was a senior at Bernards High School when we were freshmen. And it wasn't a serious dating relationship, but she hung around with him, and he -- seniors were allowed to drive to school. And he drove her. ... So you know, and it was kind of like a -- senior dating a freshman, whoa. It was almost scandalous, you know? ... I honestly think she could have her pick of whoever she really wanted to have a relationship with."
But above and beyond all her other pursuits, Streep was the perennial lead actor in everything from "The Music Man" to "Li'l Abner" to "Oklahoma."
"As a sophomore, she starred in the first musical that Bernards High produced," said Castrilli. "She starred in that as a sophomore. Now, usually they saved the starring roles for seniors. She was Marian the Librarian in our sophomore year. She was Daisy Mae in 'Li'l Abner' in our junior year. And she was Laurie in 'Oklahoma!' in our senior year -- all three starring roles.
"Once she was in 'Music Man,' you didn't, you had no idea that anybody would get a role while she was there," she said. "And it's not because the teachers favored her; she was just the best. ... And when you're the best, you should be the best."
As perfect as she was, Streep did have one failing, Castrilli said.
"Driving. I'm pretty sure that she kind of smashed up the driver's ed car, I heard," said Castrilli. "I know she smashed up the car once when I was with her. I had my license. She only had her permit, but her father gave us his beautiful, big car because we were gonna go driving around town like big shots, you know. And she wanted to practice.
"So he let me be responsible. The one with the license. So we're sitting there, and she's starting to go down a road, and she said, 'No, I don't want to go. I want to go back home and get something.' I said, 'All right.' So she just turned and hit the gas and BAM -- into a telephone pole.
"We got out, and there was this dent in the trunk and the bumper. And it was just awful. There was no way to hide it. ... When we went home, it was not a happy household."
Michael Posnick taught at the Yale School of Drama in the mid-1970s, when Streep enrolled after graduating from Vassar College. He still remembers the first time he noticed her.
"The first time I saw her work was in an acting exercise in one of the studios at the drama school," said Posnick. "And it was, I'd say, about an hour-long, wordless exercise, where the actors were working on a Chekhov play called 'Three Sisters.' And the actors just kind of moved about the stage, maybe interacted some. But I'm thinking it was an opportunity to kind of discover their characters in a particular space.
"There is this woman, on the sofa, face down, reading a book. And it was Meryl Streep.