Performing in the face of huge crowds and big, fast college defenders wasn't so hard after all, he figured. It's still football.
"He was like, 'Oh, this is easy,'" Cooper said. "I didn't have a big game that day, but I could see it was easy."
Cooper didn't break out as a freshman star until later for the Crimson Tide. But both have shined this season and get their biggest opportunity on Monday -- against the terrific defense of top-ranked Notre Dame with a BCS championship on the line.
The tailback Yeldon and receiver Cooper have already put up nice numbers and plays that helped put the Tide into this position.
Alabama beat LSU on Yeldon's 28-yard screen pass in the last minute. Cooper's late 45-yard touchdown catch was the final score of a 32-28 win over Georgia in the Southeastern Conference championship, when Yeldon ran for a season-high 153 yards.
It's nothing unusual for Nick Saban to call on the youngsters to play pivotal roles. Yeldon follows 2009 Heisman Trophy winner Mark Ingram and 2011 finalist Trent Richardson in a string of quick-learning tailbacks.
And Cooper is challenging Julio Jones' freshman receiving records for Alabama.
"Coach Saban always says, 'If you're good enough, you're old enough,'" Cooper said. "If you're good enough to play and you show the maturity, then they'll allow you to do that."
Their freshman finale will be the biggest test to their maturity.
Yeldon has run for 1,000 yards as Eddie Lacy's backfield-mate even though he hasn't started a game. Together, they lead a running game that has produced 35 touchdowns and 225 yards a game.
They'll face a sturdy front seven on a defense that has yielded just two rushing touchdowns in 12 games.
Both freshmen spoke to reporters for the first time this season at Saturday's BCS media day because Saban doesn't allow freshmen to do interviews -- title game rules force them to be available. Their abilities have been on display all season, though.
Lacy, a junior, has worked through nagging early-season injuries to rush for 1,182 yards and 16 touchdowns. Alongside him, Yeldon's 6.5-yard average per carry is tops among the SEC's 15 leading rushers.
Both Yeldon and Cooper enrolled a year ago and went through spring practice. The 6-foot-2, 216-pound Yeldon capped it with an MVP performance in the spring game that didn't just impress fans but teammates.
"I didn't really know much about him because he hadn't really been running much with the (starters) in the spring," Alabama center Barrett Jones said. "I was just kind of like, 'Who is this guy?' T.J. is just such a freak specimen."
Surrounded by cameras and tape recorders, Yeldon acknowledged that he's "not really a people person."
"I don't even like talking," Yeldon said, meaning Saban's policy probably came as a relief.
As for playing before millions for college football's biggest prize, he doesn't offer much insight.
"It's very exciting, but I don't know how to explain it," said Yeldon, who has received occasional postgame counsel from both Richardson and Ingram. "It's pretty fun."
Cooper lets his excitement show a little more. He said he's spent time this week envisioning himself making big plays, but added he always does that before a game.
"It's a great opportunity," Cooper said. "That's what we've worked so hard for all our lives. It's a great opportunity and I'm happy to be able to showcase it here in Miami for the national championship."
He has 53 catches for 895 yards and a school freshman record nine touchdown catches. Cooper needs five receptions and 29 yards to break Jones' marks set in 2008, and the Atlanta Falcons receiver is a fan.
"He's a great player," Jones said on Friday. "He's just got to stay focused and continue to do what he's doing. Stay humble, stay humble and keep working. The sky's the limit, especially coming from a program like Alabama because you know he's going to be coached great there and (know) how to handle success."
After all, Ingram won the Heisman as a sophomore. If Lacy leaves for the NFL -- he said Saturday he will make up his mind after the game -- Yeldon would be the lead man with whoever takes over his "backup" role.
Cooper will be joined by fellow freshman Chris Black, who was a little more highly rated but missed the season with an injury.
"It's going to be pretty scary for the defenses that are going to be defending us," Yeldon said.