Does it matter what we believe about creation and the age of the earth?

Should a Christian worry about 6 day creation and the age of the earth?

Yes!

The bible very clearly teaches that God made everything in 6 normal, 24-hour days. He says so with His own mouth in Exodus 20:11. We know they are normal days, because every time the word day is used with a number or evening or morning in the whole old testament, it always means a normal, 24-hour day.

Jesus and the apostles interpreted Genesis as historical narrative. That includes creation in 6 days, marriage being one man and one woman for life based on a literal Adam and Eve from dust, the global flood in the days of Noah, a literal fall and rebellion in Adam leading to a cursed world and much more.

The first page of the bible shows who God is, the triune God, one God in being or essence, three Persons, Father, Son, Spirit. God says "Let Us make man in Our image, after Our likeness". God the Father, God the Spirit and God the Son is in the first three verses. The Father creating by His Word (Jesus), the Spirit hovering.

A literal, historical Genesis matters for many reasons. There is no death before Adam sinned.

Jesus asked, how can you believe His words if you don't believe in Moses?
Jesus also asked, how can you believe in heavenly things if you don't believe in earthly things