Ok, I have a couple things.
A) Could you explain the timeline? This is hella confusing for most of us. Can you explain it in DETAIL?
B) I don't think you should work on the last chapter when you JUST started making the story
C) I don't even think you should include Eirika, if she's in only the last and 3rd last chapter. It's pointless, and she has no relevance to the plot
D) This is NOT even CLOSE to Colombus discovering America
E) Even if you ignore all my points above, why is Fado bringing his 12-year old daughter on the trip? It's perilous, and she has no clue how to fight. In fact, if you're going to include someone from Sacred Stones, he'd probably bring young Ephraim, or Seth....
F) Also, the name Jack is waaaay too generic and it's not fitting of a royal.
G) Self insert's aren't necessarily bad, it's just when it's the "hero" or main character, and are either "perfect", can "hook up with a hot lady", can "cure their faults, or just "easily become the hero and badass automatically. You might want to just......make your self-insert someone else.
H) Blunt but honest is absolutely BORING, that's basically just Azama summed up. You want your character to have REAL backstory, with REAL personality.