If you grew up on Terry McMillan’s books, you know that she’s the doyenne of a particular type of black women’s lit. It hinges on sisterhood and love but doesn’t shy away from confronting how hard it can be to find happiness.

Black Gen Xers immersed in McMillan’s worlds as they came of age know, so well, the soapy middle-class fantasies she created, and though her characters are representative of a narrow slice of the black middle class, they appeal across racial and gender lines, and have done so for decades. This may be why her audience spans not just her boomer contemporaries but their children and in some cases grandchildren.

McMillan, who grew up in Michigan and published her first novel in 1987, is about to release her 12th novel, It’s Not All Downhill from Here (Ballantine, Mar.). Her career path has been an unusually direct one for someone in her line of work: she sold her first stories while still an undergrad at the University of California, Berkeley. Shortly after graduating, she got her first book contract. The closest she ever had to a nine to five, in her estimation, is some word processing work she did for other students when she was in college.

In McMillan’s new book, her protagonist, Loretha Curry, is 68—the same age as the author. And, like McMillan, Loretha seems to have everything: she runs a successful beauty empire and has a wealth of close friends. She is thrown a curveball, though, when she’s unexpectedly widowed. McMillan, who isn’t dealing with such upheaval, is nonetheless eager to defy the assumption that, at her age, life is going in the wrong direction.

McMillan personifies the idea encapsulated in the title of her new book. On the phone from her home in California, she is funny and charming. She’s also wise enough to know that though she knows a lot, she can’t afford to stop learning. Maybe this is due, in some small part, to her beginnings as an author. After initially struggling to find an audience, she became a household name. That feat is thanks largely to her fourth novel, 1992’s Waiting to Exhale. The book spent months on bestseller lists, and, according to McMillan’s agent, Molly Friedrich at the Friedrich Agency, her books have sold, in total, roughly 15 million copies worldwide.

Explaining that her books focus not just on relationships but also on life after relationships end, McMillan says that everything she writes is, on some level, about empowerment. “There are certain things that you are willing to be patient and a little tolerant about, and there are some things that don’t make any sense,” she adds.

In It’s All Downhill from Here, McMillan’s characters are older than in previous books, but her message is still basically the same. “I don’t feel like it’s really all downhill from here, but it comes down to some degree to choices,” she says. “Being old is a frame of mind. Aging is a beautiful thing, if you do it right and take care of yourself. I’m not trying to look 40, but I would prefer to slide into home, if at all possible. I know people think that you stop existing as a sexual being, stop being able to fall in love. But your life is still going on after 60.”

Though McMillan has been hugely successful, her early days as an author were a grind. She promoted her debut novel, Mama, to indie booksellers largely on her own after the book’s publisher did little on that front. She says her publisher’s publicist was displeased at the author’s efforts—particularly McMillan’s decision to write a letter to the president of Barnes & Noble. “I wrote everybody,” McMillan recalls. “They sell toothpaste on TV because you have to advertise to get sales. If no one knows your book exists, how can they buy it?”

McMillan says the industry has changed over the years, adding that the most dramatic shift is in the role of social media in promoting books. With more than 250,000 followers on Twitter, she thinks social media is a great leveler and, among other things, allows marginalized writers to reach their potential readers and increases their value to publishers. “Book tours are expensive,” she notes, “but Instagram, Twitter—those are things anyone can use.”

McMillan is forthcoming about commercial success, but does she ever lose sleep over the critics? She has won an NAACP Image Award and an American Book Award, but says, “I don’t care so much about the awards as I do about the writing. That’s what makes a difference. I’m not trying to gussy up the voice of my characters. A good story is a good story. I’m interested in people gaining something when they read books that I have written. I’m not writing for the award committees; I’m writing for the reader.”

While McMillan has maintained a loyal fan base, she’s also paved the way for a whole generation of writers. She helped move into the mainstream the idea that black people’s day-to-day reality isn’t about being secondary characters in the stories of white people’s lives. At a time when black characters in fiction were likely to either be suffering or be painted as tropes, McMillan’s characters were refreshingly focused on their own goals and happiness. For the writers who have come after her in genres ranging from science fiction to romance, McMillan helped create a literary tradition that demands respect for writers of color and for their characters.

“Ever since I found out we can be anything and do anything, I’ve approached life that way,” McMillan says. “We learn from the things that we go through.”

In her advice for other writers, McMillan stands firm that the most important thing is self-belief: “You should just tell the story that you want to tell. Sometimes a book can change a life. That’s the beauty of a book: you have no idea what impact your words can have. It’s an exploration—one that’s done out of respect and love.”