EllamayNewsome
Nightshade (OC/Reader), better known as Belladonna Ashcroft, was a Commission agent for 22 years - though not 22 chronological years. An assassin like Five, Belladonna was one of the Commission's best agents. She joined at 27 and has only aged ten years since, making her chronologically 37.
However, because of the countless missions that sent her travelling through different points in time, she has personally experienced the equivalent of 22 years serving the Commission.
The same applies to her relationship with Five. They've been together for approximately 25-30 years by the time they've personally experienced together, rather than 25-30 actual calendar years. Their lives have been shaped by time travel, missions and timelines that don't always move at the same pace as their original one.
Belladonna is also one of the children born with powers from the Marigold, but unlike the Hargreeves siblings, she was never adopted.
After the Season 3 reset, everything changes. The Commission is gone, the timelines have been rewritten, and Belladonna's body has changed - but her memories haven't.