Q.How Long Do Wax Myrtle Trees Live In Central Florida?
We bought a small, young wax myrtle tree when we first built our house in 1985. We were told it was about 5 years old, and they generally had a 15-year life span. — Our tree is is still growing 38 years later, making it approximately 43 years old! It’s leaning over, but full of berries and the birds love it!! It has a will to live!! What is the actual normal life-span of these trees! I love it, and hope to have this one for many more years to come! Thank you!

Certified GKH Gardening Expert
They can live for around 30 years with perfect care. This is not to say that it can't live longer, but I would consider it "aged".
Here is some information on the tree:
https://www.gardeningknowhow.com/ornamental/trees/wax-myrtle/wax-myrtle-care.htm