Well, if we base her age to dragons she's really still a child who have come of age that's why she act like that so it's not weird at all and besides there's little to none who comes to be a threat to her except her own kind so far in the story thus her innocence was kept until now. But for her as the FL I just hope they won't rush it and have a good context as to how their feelings developed not just because they're living together ╮( ̄▽ ̄)╭

I hope Rurin does not end up as the FL
It's just weird with how childish and child like she is
(my opinion)