While there's nothing wrong with being happy about positive changes in our lives, on our latest Growing in Grace program, Mike Kapler and I talk about the Apostle Paul's "testimony" in Philippians 3 that isn't based at all upon any change from bad behavior to good behavior.
In fact his testimony was that he once strove to be the best of the best of the righteous people, but he chucked it all aside and counted it all as loss so that he would be found in Christ and Christ alone!