Two days later his senior season, which was riddled with ankle and foot injuries, ended in disappointment as Blue Ridge High School was upset by Chandler Seton Catholic 28-7 in the Division IV championship game.
"It feels great to sign that paperwork," Cox said. "I feel very confident with my decision and I'm very happy. I'm glad that I committed early and was able to focus on my senior season and not worry about recruiting.
"I had a high ankle sprain in the beginning of the year and that really held me back. Later in the season I broke my right foot. I missed five games and yesterday (in the championship game) I was trying to get in for a few plays on offense and defense. I'm bummed we lost but at least I got to end the season playing with a lot of guys I've been playing with since sixth grade. I had a great teammates and players backing me up and I'm really proud of all of them."
Looking back, as disappointed as Cox has been with never being 100 percent healthy during his senior season, he realizes now how beneficial it was to verbally commit early in the summer.
"As I was going through the injuries Arizona State always told me that I was still their guy," Cox recalled, "and they said that they would never back down. That was just another reason why I never considered other schools after I made my decision to commit to ASU."
The linebacker added that Notre Dame, the program ASU eventually beat for Cox's services, did stop pursuing him following his pledge to the Sun Devils, but that programs such as Washington and Washington State were still inquiring about him during the season. They were however told immediately that Cox had no desire to entertain other recruiting options.
While Friday afternoon's loss in the championship game was naturally disheartening for Cox, his evening was uplifted by the Sun Devils' thrilling Territorial Cup victory over the Wildcats 41-34, a contest he was able to view that night.
"I was really happy with their performance and really fired up," Cox admitted. "That was obviously the best part of that day. I watched the fourth quarter and saw how well the defense played (outscoring Arizona 24-7 in that period). I have a good relationship with Jaxon Hood and I'm fired up to play on the same side of the ball with him and the other guys.
"There so much athleticism and this is such a young team. Everyone is buying into Coach Graham and he is recruiting guys with great character, discipline and good work ethic. That is something that means a lot to me and one of the main reasons why I picked ASU. I'm excited seeing all this take place."
While the 6-3 230-pound Cox, a four-star prospect, is ranked by Scout.com as the nation's #1 fullback (a position some schools recruited him at), he's slated to play at linebacker for the Sun Devils.
"They (the ASU coaches) want me to play the Devil backer position," Cox stated. "So I will be playing some defensive end and some outside linebacker. It's very versatile and I can also move inside too. It's a very athletic position and I'm excited to get into it.
Being one of the top 2013 prospects in the state, Cox is well aware of the impact he can make in regards to ASU's recruiting in Arizona. Ultimately, it's an aspect that the linebacker takes great pride in.
"The coaches are excited for me to get there and help the guys buy in," Cox explained, "and they think I can really help with the recruiting process. Now that I made my decision I can help other guys make their decision as well. The coaches feel I can really make a difference.
"I've built really good relationships with Jaxon Hood and D.J. Foster. There is a lot of pride playing with local guys, and running out of the Tillman Tunnel as a local guy playing for ASU. That's more of an impact for the fan base than being a player from out of state. When D.J. made his commitment it opened my eyes when one of the best players in the country decided to stay in-state. That helped me make my decision as well."
Cox will finish his high school studies on December 21st. Before he arrives in Tempe he has one last stop to make and it's a prestigious one: The Army All-American game on January 5th which features some of the top high school players nationwide.
"It's a huge honor," Cox said, "and with all the adversity I had this year I'm happy that I will get to play there and I know I will be healthy when it's time to play. So I hope when I get down there I can prove myself a little more and prove something for Arizona State too."
There is little doubt that much will be expected from Cox once he dons the maroon and gold and the ensuing pressure to succeed will be inevitable to say the least. Cox however is all too cognizant of that and is ready to deal with those challenges that will be presented to him.
"I do want to come in and make a difference," Cox remarked. "I have to make a stand when I'm there and I'm really excited to play there with the guys.