I think this song has a powepowerful message about realising oneself esteem and what you are made of. You start off unsure and lost and you feel like you aren't worth the effort or time but then you realise that you are worth everything
When he says I should be letting go he could be talking about holding on to hate or the past.
I'm ready to fly could be that I'm ready but on the edge, very close but not game to. Kinda like a baby bird taking it's first flight and when he says but now I'm finally to fly. You finally find the strength and courage to take off like that baby bird does when he finally flies. You are finally ready to be the best you possibly can be