rx2, a little more information would be helpful. What medium is your cutting in now and what will you be tranplanting into? If your cutting is in spangum moss or coir then I would definitely go ahead and pot it up. If it is in some sort of fast draining potting mix in a cup then there is no rush and may be reason to wait until the roots are more mature. Also "dirt mix" makes one think of soil directly from the ground which would be a bad idea for container culture of a newly rooted cutting.