Judging from the fresh, clean and supple appearance of the leaves in this photograph, the leaves are probably only a few hours old. The central stem too is an indicator of the plant’s age. Rather than being brown and woody, the stem of this plant is red and soft. This is one of the clearest indicators of a young plant.
The photograph is almost perfectly focussed on the border of the bottom-most leaf. This, along with the contrast of the leaf with the background, makes the jagged edge of the leaf distinctly visible.