And God called the light Day, and the darkness he called Night. And the evening and the morning were the first day.
— Genesis 1:5
Biblical days run from sunset to sunset, rather than from midnight to midnight, but this "first day" of creation would be what we now call Sunday.
And God blessed the seventh day, and sanctified it: because that in it he had rested from all his work which God created and made.
— Genesis 2:3
The seventh day, the sabbath, is from sunset on Friday to sunset on Saturday.
There is no disagreement from Christian denominations that Saturday is the sabbath day of the Bible:
It was the Catholic church that declared that Sunday would be a solemn day for Christians, but they don't deny that the Bible designates Saturday as the Sabbath day:
The seventh day of the week among the Hebrews, the day being counted from sunset to sunset, that is, from Friday evening to Saturday evening.
CATHOLIC ENCYCLOPEDIA: Sabbath
But you may read the Bible from Genesis to Revelation, and you will not find a single line authorizing the sanctification of Sunday. The Scriptures enforce the religious observance of Saturday, a day which we never sanctify.
— James Cardinal Gibbons, The Faith of our Fathers.
— Roman Catholic and Protestant Confessions about Sunday
Also, there was no "year 0"; 1 BC was immediately followed by AD 1 (they of course didn't use that terminology at the time).
And it's most likely Jesus was born in, or about, 4 BC.