She gained 16 national titles from Jr Olympic and Youth National meets and made world teams for the 2015 World Youth Championships and the 2016 World U20 Championships. While representing USA, Irby got the silver in the 400 meters running 51.79 (U18 - 2015) and 51.39 (U20 - 2016). She also ran on the 4X400 relay both years winning gold and in the 4X100 prelim (U20 - 2016) also winning gold.