at that size, it should be mature enough to flower.
possibly just is settling in from the transplanting last year.
they will bloom profusely in a sunny site, though i have seen leggy specimens in woodland shade flower more sparingly.

I bought a fringe tree that was in full bloom and it is only 1.5 feet wide by 2 feet tall. So certainly not because it is too young -- transplant adjustment or too much shade?

Maybe it was the weather this year. I live in SE Michigan. My apple and pear trees had about 10 bloosoms each, my mulberry trees had a handful of puny berries, my wild grapes have nothing, huge autumn olives had about 10 berries total. My climbing rose barely flowered, the hybrid rose that last year was covered in huge blooms all summer had no blooms. Not one. Flowering was suppressed or delayed. I can only guess it was the continuous rain, lack of sun. Other people in my area told me similar stories. Neighbors who planted vegetable gardens with plants from the store all got yields though. Blossoming is just getting going here when it should be winding down