Jackson Arnold enters 2024 with a target on his back as the first-year starting quarterback of the Oklahoma Sooners. One year ago, he was just arriving in Norman as a true freshman trying to learn Oklahoma’s offense behind Dillon Gabriel. Now, he’s been given the reigns as OU’s full-time starter. Given his youth and inexperience on the field for the Sooners, questions of how he’ll deal with the pressure of starting quarterback at a school that has produced two Heisman Trophy winners at the position since 2017. “Just block it out,” Arnold said of his plan to separate himself from outside noise….