Could it be this?
"By the Babe Unborn"
by G.K. Chesterton
If trees were tall and grasses short,
As in some crazy tale,
If here and there a sea were blue
Beyond the breaking pale,
If a fixed fire hung in the air
To warm me one day through,
If deep green hair grew on great hills,
I know what I should do.
In dark I lie; dreaming that there
Are great eyes cold or kind,
And twisted streets and silent doors,
And living men behind.
Let storm clouds come: better an hour,
And leave to weep and fight,
Than all the ages I have ruled
The empires of the night.
I think that if they gave me leave
Within the world to stand,
I would be good through all the day
I spent in fairyland.
They should not hear a word from me
Of selfishness or scorn,
If only I could find the door,
If only I were born.