Where exactly was she going to look? She has nothing to go on except an early memory of being left behind. Even the Sith cave couldn’t show her an image of her parents, which would have been as easy way to seduce her.
If you cling to the belief your parents are coming back to the place they left you, there’s a big psychological hangup about leaving that place, even for a day. It’s not rational or realistic to anyone else but her, as most forlorn hopes tend to be.It’s actually a very compelling dramatic element to her story, however where I think Dre has a problem is that it needs to be more essential to her personality/decisions. Definitly don’t think the “she should act her age” argument holds any water though.
I say act her age, because the character is kept passive and uninformed seemingly never exploring any other possibilities or solutions for her situation, because it’s convenient to the writers, not because it seems the logical choice for a person of her age, skill set, and intelligence to not ever explore any other options. The only reason given for her staying so passive and inactive is a fool’s hope, and the films make a compelling case, that she is no fool, and really rather impulsive and pro-active in her actions, once she meets BB-8 and Finn.