Dowling was rated a four-star prospect by both Scout.com and Rivals.com out of Southeast High School while also ranked as the No. 5 safety in the country by Scout.com. He participated in the 2010 Under Armour All-American Game and was named to the Top 150 Dream Team by PrepStar Magazine. Dowling recorded 58 tackles, 14 interceptions, two returns for touchdowns and three blocked punts during his senior season. The versatile Dowling also had 241 yards receiving and five touchdowns as a senior. During his junior campaign, Dowling had 48 tackles, eight pass deflections and 14 interceptions on his way to being named 4A FSWA All-State selection in 2008. He was also a member of the track team at Southeast High School.