Turning dreams into reality should be everyone's goal in life, yet a majority of students enrolled in college have no idea why they are going other than "it's the appropriate thing to do".
This is an important observation. It's a little presumptuous to say that you know how most students are, though, so you might want to revise so that it says, "My adviser pointed out to me that most students..."
This is relevant to some discussions I have had with Linmark lately, too!
I think you should not mention that you made the decision in kindergarten. It is much better to say the idea has been developing since grade school. To say that you stuck with an idea you had when you were 5 is not as impressive as saying you have been working toward this for, say, 8 years. It is a subtle difference! :-)
Near the beginning, I think you need to add some sentences about your teaching philsophy, your ideas about education reform efforts that have been made recently, and so forth. If you claim to be different from other students in teaching programs, prove it by discussing issues that aspiring teachers discuss. Google:
education reform major issues.
Also google:
philosophy of education
:-)