Pom Klementieff was 31 in Avengers: Endgame when she played the character 'Mantis'.
That was over 5 years ago in 2019.
Today she is 38, and has starred in 33 movies in total, 10 of those since Avengers: Endgame was released.
In Avengers: Endgame, I think Pom Klementieff looks: