The creators have been pretty consistent in dodging actual numbers because they wanna leave it up for people to relate to the characters – to see them the ages they want. Everyone is going to see different ages for their favorite characters, and that’s okay. And yes, Josh Keaton is an official source, just as much as Jeremy Shada confirming Lance is Cuban and Tyler Labine confirming Hunk is Samoan are also official sources.
There is no massive age gap between the characters either, as shown in this interview with Montgomery and Dos Santos from last year:
The official website and the comics, written by Tim Hedrick and Mitch Iverson themselves also mention the five paladins are teenagers. No explicit ages are given.
The video that talks about the ages doesn’t confirm any numbers either. Hunk, Keith and Lance are said to be late teens, which is not a number set down in stone – and Shiro was given “that’s a safe zone” when asked if he was 25. Meaning he could be younger or older than 25, it’s up to you.
This was reiterated by Tim Hedrick himself last year:
Multiple people are going around saying Hunk, Keith and Lance are canonically 16/17 and that Shiro is canonically 25. It’s a nice headcanon, but it’s not how everyone sees it due to multiple official sources saying nothing is confirmed. People see things differently, it’s not a hard concept to grasp. Attacking people – both fans and creators – because of a headcanon is not something any of the people involved with the show condone, as they’ve mentioned multiple times.
EDIT: Because I missed these and people were kind enough to remind me:
Jeremy Shada said he believes Lance is supposed to be 16 and all paladins are supposed to be teenagers, some slightly older, some slightly younger, but they are all around that age. Source.
Tyler Labine mentioned Hunk is 17. Source (around 15 minutes). He also mentions all paladins are teenagers during the first two questions in the video.
theclumsiestninja 