Her indoor personal best is 18.82 metres (Birmingham 2022). At the 2019 World Championships in Doha she threw a new outdoor personal best of 18.61m to qualify for the final.[4] By throwing over the 18.50m required she qualified for the Tokyo Olympics in 2020. She competed in the event, throwing 17.81m in the qualifying round to finish in 17th place.
Domestically, as of 2023 McKinna is a six-time national champion, winning both indoors and outdoors in 2019, outdoors again in 2020 and 2021, and indoors in 2022 and 2023
She is the granddaughter of the former Norwich City footballer and manager Dave Stringer.[5] McKinna works for Norfolk Constabulary as a detention custody officer.[6]