[2] As a youngster, Brier held seven Welsh age groups records, including in the long jump event.

[3] In May 2014, Brier, Mica Moore, Hannah Thomas, and Rachel Johncock broke the Welsh 4 × 100 metres relay national record at the Loughborough International event.

[7] At the 2015 England Athletics Indoor Under-20s Championships, she set a Welsh under-20s record time of 11.44 seconds for the 100 metres event.

[5] She won the 100 metres event at the 2022 Welsh National Championships, in a wind-assisted time of 11.38 seconds.

[15] Her brother Joe Brier was also selected for the Games, and they were one of four pairs of Welsh siblings scheduled to compete.