"As a freshman, we knew her speed was there immediately," Russo said. "She's extremely fast, and you can't hide that. But she was very unconfident and was not sure what to do with the type of speed that she has.
"It was hard for her uncertainty not to affect her results. Running, especially in longer distances, is so much confidence and mental. If you're not mentally prepared, especially at that speed, just the slightest loss of focus can really change the whole race and the outcome."
Carson arrived at Haddonfield with a knowledge of her opponents. She remembers going up against athletes she idolized such as Michelle Brown, who graduated from Seneca in 2010 and currently runs at Notre Dame.
"I was definitely nervous," Carson said. "As a freshman, you're the new kid on the block and everyone is wondering what you can do. Going up against them was tough, but it made me train harder and realize the potential that I had."
Carson's nervous approach no longer exists. As she developed into a Group 2 champion in the long jump last year and a 55-meter indoor champion in Group 1 this winter, she finally understood her ability.
She holds school records in the 100- and 200-meter dashes and the long jump, and as a part of the 4x100, 4x200, and shuttle hurdle relays.
"I really started to gain some confidence and realize I really am one of the elite sprinters in the state and in the group," said Carson, who will be joining Brown at Notre Dame in the fall.
"I just need to be confident to go out there and do what I can."
Added Russo: "It was really neat walking out of the building next to her saying, 'Wow Emily, you were the fastest girl in the 55 today.' I think she really enjoyed that. I think that really helped her confidence."
Now, Carson's approach is much different. She knows how good she is and, instead of scouting out the opposition, realizes that all eyes are on her.
"I still do look around," Carson said. "But I feel like when I step on the line that I earned my spot here, and there's probably a lot of kids that look at me and are maybe intimidated."
Contact Nick Carroll at email@example.com. Follow on Twitter @NickJCarroll.