The first time I noticed June Squibb was her Oscar-nominated performance in Alexander Payne’s “Nebraska” in 2013. She’d done a lot of other movies before that and even more since, acting for 78 years with more than a hundred credits to her name. Now, at age 94, she’s appearing simultaneously in two films being shown in theaters.

One is her very small part as Nostalgia in Pixar’s mega-hit, “Inside Out 2.” The other is her first starring role in Josh Margolin’s “Thelma.”

Squibb plays the title character, a nonagenarian living on her own who hasn’t gone out much since her husband died two years ago. Her slacker grandson, Daniel (Fred Hechinger), drops by regularly to spend time with her and explain how to use her computer, which she is baffled by. Having gone through similar scenes with my mother when she was in her eighties, I completely related to his patiently explaining how to scroll down a screen, exit from pop-up ads, and do something as simple as check email.

One day, when Daniel isn’t there, Thelma opens an email attachment of a man singing a song she likes. Not realizing it’s spam, she replies and unwittingly gets sucked into a scam that costs her $10,000 in cash. Disappointed in herself for falling for it, angry at whoever took her money, and refusing to be a victim, she vows revenge when the police offer no help.

From there, we’re into an action movie, complete with a soundtrack that could come from any “Mission: Impossible” score. In fact, it’s seeing Tom Cruise in one of those movies — doing his own running and leaping between buildings — that gives Thelma the impetus she needs to set out on her own mission. Meanwhile, her daughter, Gail (Parker Posey) and son-in-law, Alan (Clark Gregg), are freaked out by Thelma’s disappearance because they’re not only helicopter parents to Daniel, their son, but treat Thelma like someone who can’t function on her own, either. The irony is that Gail and Alan can barely get through even a simple conversation, let alone a crisis, without petty bickering.

Along the way, Thelma calls some friends for help, but is distressed to find out they’re all dead, except for Ben (Richard Roundtree), who now calls an assisted living facility home. It’s during her visit to him that we get some images of what life is really like for senior citizens wasting away in such places, and we can see why Thelma is determined to stay independent and take care of herself. Again, I had flashbacks to the last years of my mother’s life when she could no longer live alone.

Fortunately, Margolin doesn’t exploit elder issues like failing memory, the risk of falling, and utter boredom, but he doesn’t shy away from them, either. In fact, he strikes a nice balance that doesn’t distract from the comical adventure that drives the plot. Margolin not only directed “Thelma,” but wrote and edited it, too. In doing so, he displays some crisp comic timing, with only one lull involving Daniel having a breakdown and calling his ex-girlfriend.

As the youngest member of the “Thelma” ensemble, Hechinger (in a part that would have been played by Seth Green twenty years ago) more than holds his own in his scenes with screen veterans six and seven decades older. In his final movie before dying last October, Roundtree plays Ben with a nice dignity, and I was glad Margolin didn’t slip in a cheap “Shaft” reference. Oh, and there’s another octogenarian actor who makes an appearance in the movie’s climax — but I won’t give away their identity here.

For his first big-screen movie, Margolin based the story on his own grandmother Thelma being ripped off by con artists. He also took some of the things he heard her say and put them into the script. As for Squibb, she comes alive and lights up the screen every time the camera is on her. It’s clear she had as much fun making the movie as I did watching it.

It’s interesting this movie didn’t go straight to a streaming platform, as small movies like this tend to do in our current entertainment environment. Instead, it’s playing in art houses, where customers are typically older than those who go to the megaplexes for comic book movies. “Thelma” may set a record for an action movie that not only stars a group of talented oldsters but also sells tickets at a senior citizen discount.

Other than the scene with Daniel’s breakdown, I can’t find faults with “Thelma,” so I recommend it — regardless of your age.

My rating: 9 out of 10, which means it will be on my year-end Best Movies Of 2024 list. In theaters now.

P.S. Don’t run out when the credits start or you’ll miss something special.