‘I believe…’ That’s how the Apostle’s Creed begins. In English. In Latin, it begins ‘Credo…’
And the very beginning of the Apostle’s Creed is ‘Credo in Deum, Patrem omnipotentem, Creatorem caeli et terrae.’ ‘I believe in God the Father omnipotent, maker of heaven and earth.’
However one defines ‘maker’ of heaven and earth (whether in terms of the traditional belief that God literally made, and makes, everything that is, or in the sometimes adopted rather looser notion that God ‘makes’ stuff via evolutionary process), Christians have since at least the 3rd century confessed that God is responsible for everything that exists.
And that’s why Christian Churches celebrating ‘evolution’ Sunday have stepped outside of the Church and abandoned Christian belief. ‘Evolution’ Sunday is all about removing God from the process of creation. Any Church that actually can, and does, remove God from the equation is no Church.
Hence, the current effort to get Churches to observe ‘Creation Sunday’ rather than ‘Evolution Sunday’ is a good thing. Unbelievers are within their rights to exclude God. Christians aren’t, or they cease to be Christian in any real or meaningful sense of the word.
Feel free to celebrate whatever you like. Just don’t call yourself a member of the Community of Faith if you can – with a straight face – exclude God from life.