I don't think it's envy so much as just "Wow, these other American girls really are too big..." (possibly with a "will I be like that too, in the future?")
You're Gambier Bay, yes? Thank you for taking care of my little sister.My! You're mistaken, I'm the one taking care of Gambier.Hey Sam, what're you standing there for, come here!Samuel, I've heard a lot about how protective you are too.Ah, sure.Sam's a really good girl.Johnston!! It's really you, Johnston!?We've been waiting for you so long, Fletcher!