I know the Bible says that "all the days that Adam lived were 930 years". I also know that God said "in the day that you eat of it [the Tree of Knowledge of Good and Evil] you shall surely die." I'm going to assume that Adam knew that "to die" was the opposite of "to live" and that eating the fruit would be a new paradigm, a game changer. So an argument can be made that the counting of "all the days that Adam lived" began on the day of the Fall.
How long were Adam and Eve in the garden before the Fall? A day, a week, a year, 5,000 years?
Actually, it says "dying you shall die." He began to die on that day. But regardless, its says all the days that he lived. This would go from the day God breathed the "breath of life" into him, and he came to life (Genesis 2:7...same Hebrew word as in 5:5....) So yo would date from then.