Written By: Eliza Berman

Living in the YouTube era, it’s no longer entirely surprising to see a 5-year-old piano prodigy or a breakdancing toddler go viral. Half a century ago, those baby Einsteins got their 15 minutes of fame in a more old-fashioned medium: the back pages of LIFE magazine.

Fifteen-month-old Jean Anne Evans was one such child. The Texan toddler was born into a family of ranchers and horseback riders, and first straddled a saddle (with her mother in tow) at the tender age of one month. When LIFE photographer Alan Grant visited her family’s farm near Fort Davis, he found the girl holding her own atop her 25-year-old horse, Toy Boy.

Despite her prowess, LIFE wrote, she occasionally “betrays her years by dropping off to sleep suddenly in mid-roundup.” Thankfully, her mother’s saddle made for just the place to take a nap.

Liz Ronk edited this gallery for LIFE.com. Follow her on Twitter @lizabethronk.

The Youngest Cowgirl in 1955

The Youngest Cowgirl in 1955

Allan Grant The LIFE Picture Collection/Getty Images

The Youngest Cowgirl in 1955

The Youngest Cowgirl in 1955

Allan Grant The LIFE Picture Collection/Getty Images

The Youngest Cowgirl in 1955

The Youngest Cowgirl in 1955

Allan Grant The LIFE Picture Collection/Getty Images

The Youngest Cowgirl in 1955

The Youngest Cowgirl in 1955

Allan Grant The LIFE Picture Collection/Getty Images

The Youngest Cowgirl in 1955

The Youngest Cowgirl in 1955

Allan Grant The LIFE Picture Collection/Getty Images

The Youngest Cowgirl in 1955

The Youngest Cowgirl in 1955

Allan Grant The LIFE Picture Collection/Getty Images

The Youngest Cowgirl in 1955

The Youngest Cowgirl in 1955

Allan Grant The LIFE Picture Collection/Getty Images

The Youngest Cowgirl in 1955

The Youngest Cowgirl in 1955

Allan Grant The LIFE Picture Collection/Getty Images

The Youngest Cowgirl in 1955

The Youngest Cowgirl in 1955

Allan Grant The LIFE Picture Collection/Getty Images

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