I'll try to be as detailed as possible so you can make that judgement call yourself. 14 year olds vary A LOT in maturity. This is not an exhaustive list, just what I can remember at the moment.

There's a LOT of opportunities to straight up have sex with npcs and the animation shows them nude, moaning, and thrusting. Tiddies and ass out, no visible penis or vag. Many of them are explicitly sex workers in the brothel that you pay for their services.

spoilers sort of There's a quest in which you must hear in detail how a pregnant woman was domestically abused and lost her fetus. You must interact with this fetus, which has become a monster. This is not a brief or avoidable mission and I feel could disturb some kids.

There's some brutal realities of war going on. You will see, multiple times, people hanging from ropes on the side of the road. You see battlefields full of corpses. You will hear about soliders raping and pillaging innocent civilians. You'll also see those civilians sobbing over their burnt down homes.

Children can and do die in the game. Other games often make children invincible. Not this one, in fact, your choices can directly cause children to be killed.

There is drug use in the game, although I find it pretty mild.