we know that pidge was just starting middle school in the flashback at the end of episode 2 of season 4 because she says that she has to go through middle school without Matt there (because he will be on the kerberos mission)
most middle schoolers start at age 11 (turning 12 during the year) meaning that in the flashback pidge would have been about 12 years old. in the pilot we learned it takes months to get all the way out to kerberos so that would have taken some time.
in the pilot we are shown pidge a year after the failed kerberos mission which would have been a year and some months after the flashback in season 4 allowing the time for the kerberos mission to launch, fail, and have a 1 year anniversary of that failure. therefor pidge would have been about 14 at the time of the pilot.
we also know that pidge is 15 now which means that in canon from the time of the flashback to season 4 pidge would have aged 3 years and matt would have aged 3 years as well.
with the assumptions that the garrison is a high school program, said high school program wouldn’t send a student who hasn’t completed the program on a mission, and that most high schoolers start at age 14 (turning 15 during the year) and graduate when they are 18, then when matt went on the kerberos mission he would have been at least 18 years old.
this is also supported by the fact that keith, hunk and lance are all 17/18 year olds and were still part of the program and keith was the top student in the class but still wasn’t chosen to go on a mission. none of them were. they were all still being trained in the pilot which leads to the idea that the garrison wouldn’t send people to space until they completed the program/graduated. so again matt would have been at LEAST 18.
if he was at least 18 when he went on the mission and 3 years have passed in canon since the flashback scene, that would mean that in season 4 matt would be at least 21 years old.
Can we stop with this need to compare the accomplishments of groups/acts to each other? Yes, BTS is getting massive success. Yes, other artists have had massive success before. One doesn’t have to discredit the other.
The reason BTS is accomplishing so much now, particularly in regards to western success, is because other artists like SNSD, BoA, 2NE1, Utada Hikaru, and PSY (among others) did the hard work of introducing the idea of value in Asian music to countries that have a hard time accepting any entertainment not catered to them. It was the same thing in Japan when Kpop first started moving there. BoA and DBSK had to perform at malls like a new artist when they already had fans back home but because they did the grunt work people like SNSD and Big Bang were then allowed to go beyond the success that their predecessors found. And now the future gen groups will build off of that.
Someone on twitter said it well, other artists paved a road for BTS’ success in the west, they made it easier for them to reach the heights that they have, and now they are continuing that road. BTS is extending that path so that the next artist to come through won’t face as many obstacles as the ones that came before them. It doesn’t mean that anyone worked harder than any other artist. One group’s success doesn’t invalidate anyone else’s.
If you’re reading this, I hope today brings you something to smile about, however small that may be. And if it doesn’t, go out and find something, anything to smile about. Trust me, it’ll make you feel a bit better. Smiling always helps.