These are two different problems. Both of which are common in video games, particularly Final Fantasy.
I think the early games were aimed at a younger audience -- yes? -- then, around FVII or so, the games started to be aimed at late teenagers, and the characters were their age or just a bit older. In FVIII, I feel, the game was aimed at players who were the same age as the characters.
So here we have a fictional fantasy depiction of teenagers being child soldiers. It's less idealized than many "teen heroes save the world" stories, in that these characters often act like teenagers, self-centered and mixed up in their feelings and coming up with boneheaded, idealistic, and impractical plans (see: Rinoa, would-be freedom fighter and trust fund baby). In Squall's case he's got a serious case of "I don't care" nihilism which is a common stance at that age. (And we know some of the reasons for this, but Liv doesn't, because she hasn't played that far, and anyway, I'm not sure if it's sufficiently justified.)
We've also got the adults who put them in this situation, and that's a whole other fascinating issue.
The game doesn't fully deal with either of these issues: the immaturities of child soldiers and young people in a military organization, and the grown-ups who exploit them. But it raises those issues, which is fairly unusual for a "teenage heroes saves the world" story.
FFVIII tells that story not through social commentary but via the teenaged POV of the characters, for the gratification of teenaged players who may not be interested in much gray area. For them, Squall is COOL because he's nihilist, and Selphie is the fun party girl, Irvine is a hot bishie guy, and Rinoa is a self-insert for every pampered child like me who latched onto idealism to rebel against our parents...and so on. (Or am I oversimplifying and underestimating a teenager's POV?) I view these characters from the outside as common teenaged roles, but the game is showing them from the inside to people who are likely to be surrounded by and participating in one or more of those roles in their daily lives.
Contrast that with FFXII, which seems to be aimed at college student aged players, and which ditches teen romance for political intrigue, power struggles, and artsy riffs about history and agency and fate.
annnnnd I just got a phonecall which totally broke my concentration on where I was going with this, so I'll just leave this out here.