Maiden, I used to be nocturnal when I was younger, with one twist: When I didn't have to be at work or school, which wasn't very often, my tendency was to go to bed an hour later each day; it is what my body naturally wanted to do. I found it very difficult to fight this tendency, and getting up in the morning was usually the hardest thing I would do all day. I used to dread getting up in the morning whereas now I love it.
Now though, I'm definitely an early riser--something that has been coming on for about ten years. Now, I go to sleep at eleven pm, and wake up every morning between 5:30 and 6:00, even when I don't have to work.
I'm not sure if this change is a result of biology or my circumstances. When I was young, I lived in a big city where plenty was always going on. Now I live on a big place in the country far removed from society, where the only the wild life have a night life.
What I'm getting at is that your patterns may eventually change too.