In Zindel's The Pigman, has John matured since his freshman year in school?

In Zindel's The Pigman, John writes about being a troublemaker in school. He brags about being called the Bathroom Bomber because he used to set off tiny bombs in bathrooms during his Freshman year. He then brags about a prank he calls "the fruit rolls," which is when he gets other students in class to roll old apples at substitute teachers. John says the following about himself after bragging about his pranks:

"I gave up all that kid stuff now that I'm a sophomore. The only thing I do now that is faintly criminal is write on desks" (3-4).

This does not mean that John has matured. Someone who has a mature outlook on life wouldn't start a book that is supposed to be a "memorial epic" (5) by bragging about himself. Not only that, but as John is writing the first chapter, he has just done something very immature--he held a teenage party in Mr. Pignati's house without permission. During the party, John had his friend bring alcohol, the girls tried on the deceased wife's dresses, and police were called in to break it up. This does not demonstrate that John has matured. Even though John is the one who wants to write about his and Lorraine's friendship with the Pigman, which might seem honorable, he only suggests it to help Lorraine with her grief. Mr. Pignati died after they held that party at his house and she feels as though this pushed him into the grave. Therefore, John is not much more mature by his sophomore year. He is getting better, but he still has a way to go before one might call him mature.