As Dick Van Dyke marks a century today, he’s merrier than ever. Says his wife, Arlene Silver, “He is a little slower, but I mean, man, he’s still got it!”

The legendary entertainer recently told PEOPLE, he “feels about 13,” and though he can’t always remember what he ate for breakfast, he still has a knack for perfectly remembering his favorite show tune lyrics word for word.  “I don’t know why but I just do,” he says.

His magical turns in The Dick Van Dyke Show and the beloved classics Mary Poppins and Chitty Chitty Bang Bang made him a national treasure to multiple generations. Says Silver fondly of his legacy, “He’ll live on forever.”

But Van Dyke himself may not have registered the scope of his worldwide appeal.

“I tell him all the time, but I still don’t think he understands,” says Silver, 54. “He’s like, ‘Oh. I’ve been around a long time.’ It’s beyond that. It’s not just that you’ve been around a long time. You’re in people’s blood. In people’s hearts and souls. How many people can say that? I got fan mail the other day, a 4-year-old who loves The Dick Van Dyke Show. It’s her favorite show.  It’s so beautiful.”

After almost 20 years together, Silver says she’s learned many things from her unflappably optimistic husband. “I guess he made me feel like you’re never too old to do anything,” she says. “Because people say, ‘Oh. I’m too old at 40,’ or something. It’s like my life kind of started at 40, my new life with him.”

Indeed, at a recent PEOPLE interview and photo shoot at his home in Malibu, Van Dyke joed, “I’ve never met anyone else who was 100 so I don’t know how to act,” sang along to his favorite songs and even tooted on the trombone.

“I think of how rare it is that a person gets to do for a living, what they love to do,” he tells PEOPLE. “Most people have to go sit in an office. I never forgot that I look forward to getting up every morning and going to work, because it’s what I would’ve done for nothing. It was such fun.”

As Silver reflects on when she met Van Dyke in 2006 at the SAG Awards, she recalls, “I didn’t know a lot about him, and his fans told me, through the social media, what he means to them. I got to connect him with his fans that he never really did before, and that’s a whole, beautiful thing.”

“I just am grateful.” she says. “I’m honored to be his wife and take care of him, make him as happy as he deserves to be. I, in turn, get so many blessings and rewards, and it’s just crazy. I mean, to think that his 90th was 10 years ago and that was a big birthday, and he’s going to be 100. I’m just very grateful that he’s in good health.”

He’s totally with it,” she adds. “I just love that I’m part of this joyful movement.”