Taskmaster was born around 1996. About 11 during Budapest in early 2008, about 19-20 during the main events of Black Widow in mid-2016.
Yelena was born between September 1988 and September 1989, because she's 6 in September 1995. She was presumably born closer to September 1989, given that's already stretching Florence Pugh's age: Yelena would be 26 in Black Widow in mid-2016. Assuming she Blipped, she would then be 28-29 in the post-credits scene.
Wenwu has had the Ten Rings for about 1000 years, and was presumably about 50 when he got them, so we're looking at him being born around the 970s A.D., very shortly after Thor and Loki.
Kate Bishop is supposedly 22 in Hawkeye. We don't know if she Blipped or not though, to determine whether her date of birth is c. 2002 or c. 1997.
Carol was born around 1963 and her ageing slowed around age 25-26 in 1989. In the following 35 years, she's only aged a few years, biologically being in her late 20s/early 30s.
Yelena has an age. Taskmaster it is never given. Captain Marvel I am just directly assuming she is in her 50's closer to War Machine's age which by the way means that they could hook up like in the comics. The Mandarin also is at least thousands of years old.
