[3] Shepherd was born Do Thi Thuy Phuong in Quang Nam province, Vietnam after her parents had an affair.

[4][5][2] When she was 14 months old, her parents died in a bomb explosion, either as a double suicide or as a murder-suicide perpetuated by her father.

[4][5] Although Shepherd was also intended to die in the explosion, she was instead blown 40 feet away and only sustained damage to her legs.

[7][6] Shepherd won a gold medal at the 2023 Parapan American Games in the women's 200m individual medley SM8.

Prior to her win, she came fourth in the backstroke, butterfly, and breaststroke 100m events, and seventh in the 50m freestyle.