Except for the period between the ages of 7 and 12 when I was convinced I wanted nothing more than to be a doctor (even though I hated the sight of blood), and my second semester of college (when I still hated the sight of blood, but foolishly tried to become a nursing major, convinced they made tons more money than anyone in the education field...), I've always sort of known I wanted to teach.
I consider myself very lucky to be able to say that throughout my middle and high school years, I encountered a lot of very dedicated teachers (which is becoming more and more rare, unfortunately). They not only taught me poems and integers and Shakespeare tidbits, but they went above and beyond their job title to ensure that at the end of the day, regardless of whether or not I passed or failed, I knew I was cared for and important as an individual. They inspired me more than they know.
In deciding to become a teacher, I wanted the opportunity to give back -- to pour into someone else's life they way mine was poured into -- to teach more than just what is in the book -- to be a mentor. Because students need to know that someone cares about them and believes in them.