To help with a bit of the confusion I'm reading, I've listed out the ages, gender, and nationalities of each of the characters, along with listing who were the original members of Overwatch.
Original Members:
Gabriel "Reaper" Reyes, Male, Age Unknown, Mexican-American
Jack "Soldier 76" Morrison, Male, Age Unknown, American
Ana Amari, Female, Hypothetically Deceased, Egyptian
Torbjörn Lindholm, Male, 57, Swedish
Reinhardt Wilhelm, Male, 61, German
New Members (Joined over the course of the following 30 years), also includes villains and other characters who aren't part of Overwatch:
Hana "D.Va" Song, 19, Female, South Korean
Jamison "Junkrat" Fawkes, Male, 25, Australian
Lúcio Correia dos Santos, Male, 26, Brazilian
Lena "Tracer" Oxton, Female, 26, British [Note: Was in a time vortex for "months", afterwards would disappear for "hours" and "days" at a time until Winston invented her chronal accelerator.]
Aleksandra "Zarya" Zaryanova, Female, 28, Russian
Satya "Symmetra" Vaswani, Female, 28, Indian
Mei-Ling Zhou, Female, 31, Chinese [Was in cryogenic stasis for 10+ years.]
Fareeha "Pharah" Amari, Female, 32, Egyptian
Amélie "Widowmaker" Lacroix, Female, 33, French [Had her heart rate slowed down, which is said to dampen her emotion and turn her skin blue. It doesn't explicitly mention slowed aging, but you can make your own judgement.]
Genji Shimada, Male, 35, Japanese
Jesse McCree, Male, 37, American
Angela "Mercy" Ziegler, Female, 37, Swiss
Hanzo Shimada, Male, 38, Japanese
Mako "Roadhog" Rutledge, Male, 48, Australian
Robots:
Bastion, Genderless, 30
Zenyatta, Male, 20, Nepalese
Gorillas:
Winston, Male, 29, Outer Space
I added this to the OP to help with some lore clarifications and also added a note for anyone just driving by to complain that we're talking about this to just avoid posting in the first place.