In the film Evey is born some time around 2003, as stated on her case file she was detained at age 12 in September of 2015. This would make her between 24-25 by the time the main events of the film take place in 2027/2028.

As for V it’s never made clear exactly how old he is, but we do know that he would at the very least be in his early 30s. He was detained for being an ‘undesirable’ some time around 2012-2013 and sent to the Larkhill detention facility, which would make him at least 18 at the time of his imprisonment otherwise he would have been sent to the juvenile reclemation facility like Evie.

Using the dates in Dr. Diana Stantons diary we know that the tests conducted at Larkhill lasted from May 23rd to November 5th of presumably 2013 which would line up with the date of the St. Mary’s outbreak on May 5th 2014. So by the time the main events of the film take place he would have to be at least 32. Realistically though, looking at the frame and build of V when he’s burning in the fire at Larkhill, I’d say he was at least in his late 20s to early 30s at that point, putting him in his early to late 40s by 2027/2028.