Genesis 1-11 (roughly) is mythical, not historical. That idea that one must hold to what is essentially Young Earth Creationism as literal scientific fact in order to be a "true Christian" (or true Jew) is simply incorrect, and at least a billion will disagree with you if you say it does.
And before somebody says "well that's just a modernist cop-out" I'll have you know that allegorical interpretation of the Hebrew Scriptures (including Genesis) is at least
2,000 years old.
Of course there is a difference between claiming the creation was a short process vs. it was a recent AND short process, but either one presents insurmountable problems with the mountain of scientific evidence.
But there's always the real
cop-out that God miraculously created the universe in a week, and made it only appear
as if it were billions of years old (which I don't hold to either, in case you were wondering)! This may be well within God's power, but it also begs the question...