That's actually why I can't really hate Contessa, just pity her. She wasn't a teenager. If I remember right, she was 6 years old when she learned how not just her Earth, but ALL Earths and the countless trillions at least would die if nothing changed.
Hell, the 2nd thing she did with her power, after making sure she would remember her Trigger Vision, was find a way to kill Eden, and had to make the choice to abandon her uncle, her only remaining living family member, and the rest of her village, because there was no path that resulted in her able to both save them and kill Eden. The first thing she learned was that even with her power she would need to sacrifice the few to save the may. (Side note, I subscribe to the headcanon that the 3rd Entity, Abaddon, was a saboteur and actually used PtV to set things up for the Thinker to crash land, Fortuna to get PtV and kill her, and then for the Warrior to be something that needs to be dealt with, leading to juicy conflict/data it could swing by later to collect.)
And no, it's not fanon that she is heavily dependent on her powers, its canon. She can function without them, but pretty much all the time she's running a Path constantly, which obviously has serious consequences in regards to her development and ability to grow as a person.