Sure. Mine, and I think many others, changed precisely when I went through puberty. Early riser before, late riser after and ever since.
My grades (predictably) crashed early in high school, didn't start to recover until I discovered coffee. But that couldn't be found in my Utah high school, of course, so I either had to sneak a cup in or find someplace to "joe up" during lunch.
Additionally, six years ago I moved into an apartment with a huge east-facing window. Now I'm a natural morning person again — during the summer months.
My grades (predictably) crashed early in high school, didn't start to recover until I discovered coffee. But that couldn't be found in my Utah high school, of course, so I either had to sneak a cup in or find someplace to "joe up" during lunch.
Additionally, six years ago I moved into an apartment with a huge east-facing window. Now I'm a natural morning person again — during the summer months.