By the time Ashley Horner finishes this ultra-endurance conquest, they may be calling it “Ironwoman.”

The Virginia-based fitness trainer flew to Haiti Thursday morning to embark on a feat no other woman has accomplished: completing 50 Ironman races in 50 days. That’s a 2.4-mile swim, a 112-mile bike ride and a 26.2-mile marathon — times 50.

“I think by race No. 17, I might start to think, ‘what the heck am I doing?’ ” jokes the 34-year-old with 596,000 Instagram followers.

Horner says that in moments like those, she’ll remember why she’s attempting the feat in the first place: to raise $100,000 for the Maison Fortuné orphanage in Haiti, which she first visited in 2015, and fell in love with. The orphanage director will send her videos, photos and letters from the children every day before she embarks on a race that will have her running, biking and swimming across Haiti (twice) and 48 US states.

‘I think by race No. 17, I might start to think, “what the heck am I doing?” ’

“I know my purpose, and that’s what will keep me going,” she tells The Post. “It’s for those children in Haiti.”

Horner, a ripped and tattooed mother of three boys ages 11, 9 and 4 years old, is a lifelong athlete. The Virginia Beach, Va., resident practiced soccer for Guam’s national soccer team, has authored more than a dozen training programs and owns a gym. She’s never run an Ironman before, but has completed many ultra-endurance races, including a 1,350-mile bicycle ride from Virginia Beach to Tulsa, Okla., and a 230-mile run along Haiti’s western border.

“It’s not like I just woke up and decided to do this,” she says. “A lot of thought, preparation and training went into this.” She does strength-training four times a week, and runs, swims or bikes just about every day.

Horner will begin her first race Sunday at 9 p.m. Then she’ll fly to Florida to do it all over again. Each day, she’ll be driven in a Sprinter van to the next starting line, catching whatever sleep she can on the drives. She anticipates each race will take 12 to 16 hours, which won’t leave her a lot of time to sleep. The exhaustion will be one of the hardest challenges to overcome, she says.

“The big danger is falling asleep on the bike,” she says. “I might have whoever’s in the car behind me blow an air horn if I feel myself dozing off!”

Between resting and races, she’ll do her best to revive her weary muscles with ice baths, stretching and an electrical stimulation device by PowerDot, her sponsor.

She’ll also fuel up with a mostly ketogenic high-fat, low-sugar and carb diet — but, with the calories she’s burning every day, she’s not cutting herself off from her favorite indulgences: peanut butter and jelly sandwiches, Snickers bars and Sprite.

“I’m going to be burning about 7,000 calories a day, so at that point, I can pretty much eat whatever my body wants,” she says with a laugh. “I’m honestly more worried about actually consuming enough calories.”

Completing 50 consecutive Ironman races is possible: In 2015, the so-called “Iron Cowboy,” James Lawrence, completed the feat in each of the 50 states. (For the record: He did doze off during one bike race and crashed.)

Horner, who plans to end her adventure on Oct. 4 in Haiti, would be the first woman to match him, hopefully without the crash.

“It never sounded crazy to me because I believe wholeheartedly that I can complete it,” she says. “There’s not an ounce in me that has any doubt.”