My raywood ash was planted 6 months ago; it was about 15 ft tall. It looks very healthy, but has not grown more than a few inches. Live in northern California, San Jose area.
Certified GKH Gardening Expert
The Raywood Ash tree is listed as a fast growing tree.
It's yearly growth rate can be about 1 ft per year and will grow faster with more water and fertilizer.
Your tree sounds to be healthy and likely is just becoming established.
Here are some links with more information.
It's a bit late to transplant a tree at 15 feet, and in the first year or so it will be making new roots, and you wil not see much growth. My Raywoods were planted 6 years ago, are now 15/20 feet and gave a spectacular display of colour this fall for the first time.