Madeleine Albright made history as the first female Secretary of State. But like many women, she’s struggled with speaking up in meetings at work. Plagued by insecurity, Albright says, she would often refrain from making a point lest it be construed as “stupid” — only to have a man say the same thing, to praise from participants.

Her advice for women to overcome this issue? Think about what it looks like when you don’t speak up.

“If we are in a meeting we’re there for a reason,” she says in “Firsts,” TIME’s multimedia project featuring candid interviews with 46 groundbreaking women. “The bottom line is, if you are only there not speaking, you have created the impression that you’re not prepared to be there.”

“There’s plenty of room in the world for mediocre men,” Albright says. “There’s no room for mediocre women.”

Albright, who served as the top U.S. diplomat under President Bill Clinton from 1997 to 2001, says that, as a working mother, she did not necessarily expect to break the gender barriers in diplomacy.

“It had not occurred to me that I would ever be in a position to break a glass ceiling, particularly a woman who’s married and the mother of twins,” she says. “But the turning point did come.”