Flagg said he will attend Milford Academy (N.Y.) and plans to enroll in January for the spring semester at North Carolina.
When asked if he was still committed to the Tar Heels, he responded "Yes, definitely." He added that he is not considering any other schools.
Flagg committed to UNC on July 23, 2005, the day after receiving a scholarship offer from the Carolina staff.
"He is a great athlete," said Britt head coach Richard Bailey. "He is a little short for what some schools like out of that position (at 6-0 even). He is fast, though -- he ran a 4.43 and 4.47 at the UNC camp combined with a 37" vertical.
Flagg, who stands 6-0 and 225 pounds, recorded 98 tackles, 16 tackles for loss and five sacks in 11 games as a senior.