No exploration, no world map, weak story (?)

Help me out here, I can't decide whether to pre order or not

Hi guys. I've just gotten the game two days ago and I'm enjoying it a lot.
I guess I'm playing the game really slowly, cuz I'm only at Chapter 8 at the moment.
Just wondering, should I do Chapter 8 first or Paralogue 3 first?

hi guys, never played fire emblem before. thinking of getting it with 3ds since this game is hyped by many.

i have a question, can we do level grinding in this game? as in if i have a weak character, can i keep leveling up the character in some map before continuing with the story? (you know, like pokemon, you level up your weak pokemon before continuing) or i can only continue with the storyline and hope my weak character get stronger?