Realeanna Margot Ann U Grimmond was born on February 24, 2005, in Guyana. Raised in a household with a strong cricketing tradition, she was introduced to the sport early by her parents, who both played at the local level.

Operating as a right-handed opening batter and right-arm medium bowler, she quickly progressed through the regional age-group system, featuring for Berbice in local inter-county tournaments before earning selection for the West Indies Under-19 team at the inaugural 2023 ICC Women's Under-19 T20 World Cup.

Her domestic career gathered momentum as she took on leadership roles within Guyana's setup, captaining the Guyana Under-19 team and leading Berbice in senior inter-county competitions. In 2024, she was named in the Guyana Amazon Warriors squad for the Women's Caribbean Premier League.

Following consistent run-scoring performances in domestic tournaments like the Super50 Cup and T20 Blaze, Grimmond earned her maiden senior international call-up for the West Indies tour of England in May 2025. She made her T20I debut on May 21, 2025, followed by her ODI debut on June 4, 2025, where she scored a fluent 53 off 72 balls in Leicester.

Grimmond continued to cement her place in the senior setup through the 2025–26 and 2026 international cycles. In July 2026, during the opening ODI against Ireland Women at Bready, she registered her career-best international performance, scoring 91 off 107 balls while sharing a massive 258-run opening partnership with captain Hayley Matthews.

She maintained her presence across the white-ball calendar, featuring prominently for Guyana Amazon Warriors Women in the 2026 WCPL and continuing her international duties on the West Indies tour of Zimbabwe.