Juliet is a young girl, a fact that is overlooked by most audience members and readers. She is only 13 years old, and her behaviors reflect her lack of life experience. Juliet's responses to major life events are based on unprocessed emotions that lead to impulsive decisions.
When Juliet meets Romeo, she is immediately infatuated having spoken only a few words between them. Then, she is horrified to hear that her new beaux is the sworn enemy of her family. Yet, this doesn't stop Juliet. Upon their second encounter, Juliet says they must be married for them to continue on with their "relationship," and Romeo happily agrees. Juliet takes no time to think about her feelings or her choices. She bases her decisions solely on the first emotion that surfaces. In these examples, the emotions are lust, infatuation, and fear.
We see the same type of impulsive thinking when Juliet learns her cousin, Tybalt, has been slain and her husband has been banished. She can't control her emotions and wants to die just thinking about it all, mainly because she can't get what she wants. Romeo and Juliet try so hard to control the situation, but this leads to more conflict. Juliet then formulates a plan to fake her death, but when this plan is fowled, she ends up taking her own life.
Juliet's responses to "turning points" or major life events are the result of impulsive decisions based on mismanaged feelings. She doesn't understand that her love for Romeo is really lust, and she refuses to believe that she could live a life without a human she just met. Her age, naivety, and lack of reasoning lead to her handling every turning point in the play poorly through a childlike perspective.