Ask Mr. Smarty Plants

Southern Wax Myrtle Morella cerifera (Wax myrtle) is a handsome plant that we often recommend to people who are interested in growing a hedge. It is also known as Myrica cerifera . It is an evergreen plant that is dioecious; male (staminate) flowers and female (pistillate) flowers occur on separate plants.
Since you know that you have a female plant, Mr. Smarty Plants is assuming that it has produced fruit (berries) which means that there is a male tree in the vicinity that supplied some pollen for this to occur. You might want to explore the neighborhood to see where it is.

Since much of the nursery stock is propagated by cuttings, you are more likely to come home with a female plant. The Southern Wax Myrtle is wind pollinated, so the proximity of the male and female plants is probably not a big issue. We have been getting dust from the Sahara Desert in Austin, TX this summer.

This article from University of Florida indicates the possibility of monoecius female plants occasionally having male catkins that can pollinate the female flowers. This could be an explanation for how your plant got pollinated. If this is the case, your new plants could be pollinated from the same source. The article has nice photos so you can look for male catkins on your plant next spring.(more catkins)

I’m including a link to a previous answer that explains a similar situation with persimmons.

This last link to northscaping.com has tips for preventing transplant shock in your new plant.