I must be a Jew slimsavery, hehe, not by faith but by time
This is really an awesome thread, I like to live like the Jews to call my morning sunrise the start of the day, it's not the way I was raised, it's illogical, but it's the way I like it. I spend some time past 00:00 on weekends in front of the pc, so if I am awake and look at the time, I don't like to think it's Saturday, but rather Friday night.
To answer your question, I don't believe it's Christian or un-Christian, I'm not aware that the Bible says we have to follow the time schedule of the world or whatever time schedule. The Bible says in Genesis 1 that God created the Sun to rule over the day, and the Moon to rule over the night, he called the day day, and night night.
So in a Christian perspective, don't worry about it. God knows your heart and intentions, He doesn't care what time frame you believe in.
God bless
teraside