This may help answer your question. It sounds like you have high reading comprehension but I would also look at other measures to fill in the picture (SATs, AP classes/tests). Hope this helps.
http://www.lexile.com/DesktopDefault.aspx?view=ed&tabindex=6&tabid=18#18Is it possible to tie grade-level equivalents to Lexile measures?
There is no direct correspondence between a specific Lexile� measure and a specific grade level.
Although a student may be an excellent reader, it is incorrect to assume that he or she will comprehend text typically found at (and intended for) a higher grade level. A high Lexile measure for a student in one grade indicates that the student can read grade-level-appropriate materials at a very high comprehension rate. The student may not have the background knowledge or maturity to understand material written for an older audience. It is always necessary to preview materials prior to selecting them for a student.
It is important to note that the Lexile measure of a book refers to its text difficulty only. A Lexile measure does not address the content or quality of the book. Lexile measures are based on two well-established predictors of how difficult a text is to comprehend: word frequency and sentence length. Many other factors affect the relationship between a reader and a book, including its content, the age and interests of the reader, and the design of the actual book. The Lexile measure is a good starting point in your book-selection process, but you should always consider these other factors when making a decision about which book to choose.
