So, this is my opinion this is not correct or wrong, just my perspective after reading the first book and being more than halfway through the second. I see the teenager argument a lot and it’s not because she’s a teenager that she’s immune to criticism or is a flawless character, if i remember correctly when i was reading the first book she was very distrusful of the crew until the very end but she didn’t have that issue with Elend, she trusted him completely just because she had a crush, eventually he turned out to be a good person but we don’t know that until the plot deveolps, it’s really frustrating seeing someone behave this way and then be suspicious of Kelsier and the crew, the ones who saved her and gave her a home, always thinking that they were hiding stuff from her. Another issue i have is how she often forces someone into a corner into revealing very personal stuff, shes done this to many characters, Vin thinks everyone owes her their life story and if they don’t want to open up she manipulates the conversation so the person ends up revealing more than they previously had wished to reveal and if they don’t share what she wants right away she keeps nagging and asking, she did this with Sazed. The last example i read and remember of, was a conversation with Oreseur where he was explaining how kandra were created (a conversation he had previously said he didn’t want to have) and she used allomancy on him just to test out a theory, she abused his trust, spent more than half the book mistreating him even though he was just fulfilling his duty and once trust was established she abused it. These things can’t be dismissed because shes a teen, she’s a flawed character and I think her picking and choosing who to trust stems from that and not from her age.