If it seems like Betty White is everywhere these days, that’s because she is.

She started tweeting last month. She was roasted last week at the Friar’s Club in New York, where she was treated to a life-size cake in her image. And Thursday night, the 64-year showbiz veteran, former star of “The Mary Tyler Moore Show” and “The Golden Girls,” was at Lisner Auditoruim to discuss her career and share recollections from her book, “Betty & Friends: My Life at the Zoo,” which came out this fall. (White is at the National Zoo for a book signing Friday.)

People may say she’s overexposed — although at 90, carpe diem just seems like good sense — but see her in person, and you get what all the fuss is about. White walks onstage in a dressy black pantsuit and the crowd takes to its feet, cheering and whistling as she smiles and takes it all in. “Oh, don’t get up,” she says, and peals of laughter rip through the place.

White’s appeal stems not only from her combination of smarts, hard work, passion and lucidity, but how she makes us feel about getting old. In in dark places where we’ve filed 90-year-olds in our heads — propped up in front of a television or sitting a wheelchair — she challenges assumptions about aging and possibility. And when tells stories about the wild things in her life, the crowd goes ape.

To wit: White turned down a role in the Jack Nicholson movie “As Good As It Gets” because it included a scene where a dog gets thrown down a laundry chute. When Sam Litzinger, host of WAMU-88.5’s “Animal House ,” questions her about it onstage, she has no regrets.

“It’s a funny gag in a movie, but in real life if a kid or an old neighbor sees that, and does it, it’s not going to have a happy ending,” White says. Even though the movie was a major hit, White says, “I still wasn’t sorry I didn’t do it.”

A lifelong animal lover, White has had a 50-year affiliation with the Los Angeles Zoo, the mention of which elicits cheers from a group of National Zoo employees. Ashton Schaffer, 30, a zookeeper in the small mammal house, calls her an idol. “She’s managed to inspire so many generations of people who love animals!”

Litzinger reads a question from the audience: Someone wants to know how White accounts for her unexpected career revival. She shakes her head a little and smiles, and you can see it coming. Exact timing, pitch-perfect delivery.

“People say, ‘It’s so nice to have you back,’ ” she says. “But I have to say, ‘Guys, I’ve never been away. I’ve been doing this 64 years. Maybe it’s you that’s been away.’ ”