You’re not getting any younger.

But new research suggests that aging doesn’t necessarily mean life gets worse — or that things will go downhill for your mind or body.

In a Yale University study, almost half of older adults above age 65 actually got sharper mentally, stronger physically, or both — and a key characteristic made a major difference.

Over 60 million adults are now over the age of 65 in the US, representing about 18% of the population. And they’re living longer too — the death rate for older adults is the lowest since 1999.

In the new study, Yale researchers followed participants over 65 for 12 years, measuring their physical health (through walking speed) and their brain health (with a cognitive assessment that looked at things like short-term memory and math skills).

At the end of the study period, they found that 45.15% of participants showed improvement in cognition, walking speed, or both.

And who was more likely to improve? Those who felt more comfortable with aging.

They were found to disagre with statements like, “The older I get, the more useless I feel,” and agreed with, “I am as happy now as when I was younger.”

“If this finding was extrapolated to the entire US population, it would suggest that more than 26 million older persons are experiencing an improvement in functioning,” the study’s authors noted.

Unfortunately, many people don’t have the best attitudes about aging. One study showed that Americans age 40 and up think their cognition will decline as they age, while another suggested 80% of people falsely believed all older people develop dementia.

This can have serious consequences in the medical world. A doctor might dismiss symptoms because it’s seen as natural aging. About 1 in 5 people over 50 face this kind of ageism in the US.

Research shows that stereotypes about aging have a real impact on health. These negative beliefs can increase cognitive complains and impair performance on cognitive exams, as well as affect physical performance, motor learning, and driving performance.

The good news is the opposite is also true: positive beliefs about aging can improve health.

“Aging is often viewed as a time of inevitable and universal decline,” the study’s authors wrote. “When the health of older persons shows improvement, it tends to be viewed as an exception to the general stigmatized category of older persons.”

They said their research shows that the “predominant narrative of aging as a time of inevitable and universal decline needs to be reconsidered.”

Walking your way to better health

The researchers chose walking speed to measure physical fitness because it’s seen as a “sixth vital sign.” It requires the nervous system, heart, muscles and bones to function and work together and is a major predictor of longevity.

As you age, it can be great to get walking at any pace. But for those who can push for a faster walk, research suggests it’s better for you. A recent study found that people who walked the fastest were 43% less likely to die of any cause, compared to the slowest-walking group.

Getting that exercise will not only benefit your physical health, it will affect your cognition as you age, also.

One study showed that moderate physical activity increased brain glucose metabolism, or how efficiently the brain uses energy. Another showed execise can increase the size of brain structure important to memory and learning.

Stanford docs suggest keeping the brain sharp by doing puzzles like crosswords, learning new skills, and engaging in complex conversations.

Experts also recommend little things like parking farther away to get more walking in, getting a hearing and eye exam, and checking your blood pressure more often to stay in touch with your health to lower risk of dementia.

“It’s about making small, consistent choices that support your health over time,” Dr. Allison Sekuler, president and chief scientist at the Baycrest Academy for Research and Education, told The Post. “And remember, you’re never too young or too old to take care of your brain.”