A couple of reasons for it.

I was wasting my time in evenings on useless stuff and was mentally drained to do any productive work.

I need to change the type of industry I work in, so I feel the solid block of time in the morning with a fresh mind is the best time to learn new skills.

Also, I am single and got divorced last year. I found myself wasting time, contemplating mundane things, reading psychology forums in evenings. It was not helping me get out of the hole I was in. So I changed my schedule.