No, you're not crazy! Your teen is changing and this can be both exciting and challenging. The teen brain is undergoing so many different changes which can cause teens to be impulsive, have changes in mood, be more passionate, individuate from family, and increase involvement in their social groups. Learning more about changes the teen brain is undergoing can help increase our understanding and not take behaviours personally.
This video is a bit longer, but Dr. Siegel does a great job explaining the teen brain and the changes we often see: