A natural piece of writing fits one's style, and consequently is flows a bit more readily. I mean, an unnatural piece of writing isn't necessarily a poor piece of writing, but can be a bit broken up, and it's easier for the reader to disconnect with the content.
I'm sure it will get better. Most novels start slowly and build, even those of less fast-paced genres such as the one you're reading.
What's wrong with children's books? I'm still a child, or at least I consider myself a child. So I read novels for ages younger than me, for my age group and beyond my age group. It's irrelevant, though and doesn't influence my enjoyment and pleasure.
So Essays in Love wasn't written in his natural style? He mixes philosophical ruminations with narrative, which I guess was seen as inventive when the book came out. so far the characters' interactions don't feel organic; it feels like he's forcing the characters into the ideas that he wants to explore.
Well, I'm an old woman at 26, so I can't relate to children's books at all. In fact, I'm really poor with handling children because I can't relate to them and don't know how to talk to them at their level. But children's books are definitely necessary; if I ever have kids, I'd make them read a ton of books before I give them access to the computer/TV.
And yes, you are still a child.