Please note that we've updated the Mount & Blade II: Bannerlord save file system which requires you to take certain steps in order for your save files to be compatible with e1.7.1 and any later updates. You can find the instructions here.
When playing any multiplayer game mode/lobby the characters spawn older than they should. It happens when picking specific classes of the game, like aserai archers or imperial legionaries. Npcs from captain mode are the exception.