All Avengers-As of 2017 (Some of the birth dates are completely made up and some of the ages are tweaked/completely made up/guessed. And for those of you who don't know SO means significant other. I also apologize if the bold isn't working. For some reason it's not showing up for me.)

Name: James Buchanan "Bucky" Barnes; Age: 30/100; Birth Date: March 10, 1917; SO: OC/None

Name: Steven "Steve" Grant Rogers; Age: 29/99; Birth Date: July 4, 1918; SO: OC/None

Name: Bruce Banner; Age: 47; Birth Date: December 18, 1969; SO: Natasha Romanoff

Name: Anthony "Tony" Stark; Age: 46; Birth Date: May 29, 1970; SO: Virginia "Pepper" Potts

Name: Clinton "Clint" Francis Barton; Age: 35; Birth Date: September 7, 1981; SO: Laura Barton

Name: Samuel "Sam" Thomas Wilson; Age: 33; Birth Date: August 5, 83; SO: OC/None

Name: Natalia "Natasha Romanoff" Alianovna Romanova; Age: 32; Birth Date: January 23, 84; SO: Bruce Banner

Name: Wanda Maximoff; Age: 20; Birth Date: February 15, 97; SO: Vision

Name: Vision; Age: 2/26 (totally made up); Birth Date: June 8, 15; SO: Wanda Maximoff

Captain America and Bucky Barnes Facts (Some of the facts vary and the ages may not match up)

Steven Grant Rogers was born on July 4th, was in art school when he and James Buchanan "Bucky" Barnes decided to sign up for the war in their art class. He was 23 when he got the super-soldier serum and became Captain America in March 1941. He spent the better part of half a year as a show pony playing as "Captain America" for kids until he saved his best friend, Bucky, in October or August 1941. Then onward one and a half years or so Captain America and Bucky formed the Howling Commandos and took out Hydra facilities. Bucky was perceived to be dead in 1942 at age 25, and days later Captain America went on his last mission at the age of 24.

Captain America spent seventy years in the ice and woke up in 2012 at age 24 or 94. Weeks/months after waking up he fought with the Avengers/became an Avenger against Aliens. Two years after that, in 2014 at age 26/96, he fought The Winter Soldier, who turned out to be Bucky who was age 27/97 as he spent two live years working with Hydra. One year later he fought Ultron at age 27/97 while finding Bucky a little later who is 28/98. One year later in 2016, Bucky is found and Captain America: Civil War takes place in the summer and a few months later Bucky returns from Wakanda and weeks before the team is back together, though still a little stressed at ages 28/98 and 29/99.

Most fanfics take place in 2017 where Cap is 29 and Bucky is 30.

Author's Note: Before anyone tells me that I didn't do my research or anything, let me tell you one thing: IT HAS TAKEN ME HOURS TO PUT ALL OF THIS TOGETHER. Some of the facts won't match up with the film or comic version and some of the facts/ages won't match up how I have them written down. Some of the dates, like when Bucky "died" are not consistent with the film version as in the movie he "died" in 1944 and Cap went into the ice days later. The ages didn't make sense with all of the facts I found as it's practically impossible for Cap to be 21 in 1941 if he was born in 1918. My timeline is probably the most accurate depending on their ages/biological ages. Also, the little end part where the team is back together and such, that's mainly for the fanfic parts where Bucky is back with Steve and other things.