Why is Micah is lying all the time?

After reading half of Liar, i have discovered that Micah is this fake lying girl. She lies on  purpose and doesn’t care that she hurts people. She continues to lie all the time. Sometimes she doesn’t realize that she is lying, it just happens. The first big lie that her classmates discovered is that she lied and told her classmates that she was a boy, when really she is a girl. When her classmates found out that she was really a girl they called her a liar and the boys she was hanging out with kind of stopped talking to her. She always played basketball with these four boys and they didn’t take the news very well. After everyone fond out about her first lie everything went down hill from here on out. The boy that played basketball with Zach, he was the one didn’t stop talking to her. They actually had something between them that no one knew about. Which this all leads to the second big lie that she tells. Micah loves to run in Central Park, all the time. She was running one day in the park and Zach found her there and they decided to have a race and she is very fast and he had to keep up. The classmates didn’t know about them running together. Them running together lead to a kiss and more kisses. This leads to them secretly dating and still no ones knows about this. But when Zach ends up dying, the secret gets out by a by named Brandon and he told everyone. Well Zach had been dating a girl named Sarah and she didn’t know that Zach and Micah were dating too. When this all happened everything had been a mess since then.