Captain America - Chris Evans (b. 13th June 1981) - age 30

Tony Stark - Robert Downey Jr. - (b. 4th April 1965) - age 46

Thor Odinson - Chris Hemsworth - (b. 11th August 1983) - age 28

Bruce Banner - Mark Ruffalo - (b. 22nd November 1967) - age 43

Clint Barton - Jeremy Renner - (b. 7th January 1971) - age 40

Nick Fury - Samuel L. Jackson - (b. 21st December 1948) - age 62

Natasha Romanoff - Scarlett Johansson - (b. 22nd November 1984) - age 26

Maria Hill - Cobbie Smulders - (b. 3rd April 1982) - age 29

Loki - Tom Hiddleston - (b. 9th February 1981) - age 30

Pepper Potts - Gwyneth Paltrow - (b. 27th September 1972) - age 38

Agent Coulson - Clark Gregg - (b. 2nd April 1962) - age 49

In order of their age:

Natasha Romanoff - Scarlett Johansson - (b. 22nd November 1984) - age 26

Thor Odinson - Chris Hemsworth - (b. 11th August 1983) - age 28

Maria Hill - Cobbie Smulders - (b. 3rd April 1982) - age 29

Loki - Tom Hiddleston - (b. 9th February 1981) - age 30

Captain America - Chris Evans (b. 13th June 1981) - age 30

Pepper Potts - Gwyneth Paltrow - (b. 27th September 1972) - age 38

Clint Barton - Jeremy Renner - (b. 7th January 1971) - age 40

Bruce Banner - Mark Ruffalo - (b. 22nd November 1967) - age 43

Tony Stark - Robert Downey Jr. - (b. 4th April 1965) - age 46

Agent Coulson - Clark Gregg - (b. 2nd April 1962) - age 49

Nick Fury - Samuel L. Jackson - (b. 21st December 1948) - age 62

Age difference between cast members:

Scarlett Johansson - Samuel L. Jackson (36 years)

Scarlett Johansson - Clark Gregg (23 years)

Scarlett Johansson - Robert Downey Jr. (20 years)