The first time Aaron Cohen got hurt in a bicycle wreck, he was about 12, riding in a Wisconsin velodrome where he crashed into a kid who’d gone down, flipped over and smacked his head.

An ambulance rushed him to a hospital in Kenosha, unconscious from a concussion.

Stephen Cohen, his father, thought it was the worst thing that could possibly happen. And he was right— until Feb. 15.

Early that morning, a 25-year-old Key Biscayne man plowed into Cohen’s cycle on the Rickenbacker Causeway, and fled.

Aaron E. Cohen, born on July 7, 1975, in Northbrook, Ill., business development manager at Esserman Automotive Group, married to a Skidmore College polo teammate, father of two, and so universally beloved that the worst thing anyone can say about him is that he was always, always late for everything, died of massive injuries the following day at Jackson Memorial Hospital’s Ryder Trauma Center.

Patty Hagendorn Cohen, 34, donated her husband’s undamaged organs.

“It just seemed like such an Aaron thing to do, although we never really discussed it,’’ she said. “Aaron was the kind of guy who’d have given a kidney while he was still alive to someone he didn’t know.’’

Here is what loved ones want people to know about Aaron, who lived in The Roads:

He was a born optimist who “could never admit anything was less than awesome,’’ according to his wife.

“He would walk into a room, and no matter how many people were there, in five minutes he knew everyone,’’ said his aunt, Charlene Esserman, Stephen Cohen’s sister, married to auto magnate Ron Esserman.

He would carry daughter Lily, 3, into her preschool classroom at Temple Beth Sholom, on his shoulders. He’d bring treats for her teachers, and once bought every art project that her class made for a fundraiser — then offered her classmates’ parents a chance to buy them back for an addition donation to the school.

“He was always smiling and beaming,’’ said the temple’s Rabbi Gary Glickstein, who gave the eulogy at Cohen’s funeral. “He was among the most active of the dads in our school.’’

He baked brownies for his colleagues at Esserman, where he overhauled the computer system, started a motivational program, headed the company’s cycling team, did plumbing as needed, and was weeks away from a major career move.

“He was about to be promoted again,’’ said Ron Esserman. “He had the ability and enthusiasm and was friendly to everybody, but he didn’t give in and he got things done. He wanted to run his own dealership.’’

Aaron, already a successful consultant, earned a master’s degree from the University of Virginia’s Darden School of Business before joining his uncle’s operation — with no promises made.

“He grew up talking about car dealerships to his Uncle Ronnie,’’ said Stephen Cohen. “He thought he was the most brilliant businessman he knew.”

“Business casual’’ was a suit and tie, because, said Esserman general manager Pancho Diez-Rivas, “Aaron said business isn’t casual. … He had tremendous discipline and wanted to learn, but he was one of those rare breeds with great social skills who understood the importance of relationships. He was a great listener and he really cared about people.’’

He took pottery classes to decompress from his busy life, and did all the cooking, including making organic baby food for son Aiden, 1.

At 4, he followed his older sister, now Debra Goldman, into short-track speed skating. Both were nationally ranked, and she was bound for the Olympics — until she was hit by a car riding her bike.

He started a skeet-shooting club at Skidmore.

He proposed to his wife, a bond trader, underwater in Aruba, pulling a diamond ring from his wet suit.

When they married at a Virginia plantation, he made peanut brittle for nearly 200 gift bags.

He took up triathlons four years ago, and started running marathons last year.

He and his dad fished all over the world, from Michigan to New Zealand, where one dark night, Aaron tied flies for everyone in the fishing camp by flashlight.

“He had an uncanny ability to make everybody happy,’’ his father said.

He helped his younger sister, Sabrina, set up a martial arts/foreign study program in China, and came up with the name Academic Explorers for her venture.

“He was exactly what a big brother was supposed to be, except this leaving-me-without-him part,’’ she said.

When they were both in elementary school, Aaron wrote 15 pages of get-well messages from all of the family’s animals, living and stuffed, to Sabrina, hospitalized with appendicitis.

On the first day it snowed last year, he flew Lily to Northbrook, to go sledding.

He loved country music, which played at his funeral. Among those who attended: Chicago Cubs owner Tom Ricketts, who also owns the company where wife Patty works.

Mourners spoke of Aaron’s achievements and talents. His mother thought of the “little things.’’

“Every morning, he’d put a new little picture of Lily on Facebook, or would just say ‘Hi Mom,’ ’’ Lynn Cohen said. “It’s going to be so hard to live without that.’’

Contributions in Aaron’s memory can be made to the Aiden and Lily Cohen Trust, Stephen B. Cohen, trustee, c/o Cohen, Kelly, Olson, Dehann & Richter, 900 Ridge Rd., Suite K, Munster, IN 46321.