Is Innocence hard? I'm a casual player.
Lol, don't worry, all RPG's should be friendly enough even if you're a casual gamer.
Basically if you're in a tight spot you need to deal more damage and thus, just grind/level up to make up for the lack of skills that you might have. beating some boss under-leveled might require some luck and skill, but nothing saves him from a overleveled party you might have.

It's pretty easy to break through a RPG, providing you don't get stuck in other matters (like: "hey, where do I go next!? hello? is anybody there? what are these moon runes? oh, it's Japanese")