Don't worry, three years is still quite young in Wisteria terms.
They often tend to grow very freely when young and so don't have the energy left to flower, is yours growing vigorously?
It may be worth giving a dose of slow release high potash fertiliser to encourage flowering.
Also, pruning is essential to get the wood to ripen and buds to form. Prune all new shoots (the long green stemmed ones) back to one foot in July to let the sun get to them. Then prune them back again to 3 to 4 inches in January. Do this every year and you will build up a framework of short flowering stems (called spurs).
Wisterias are famous for not flowering for a few years. I had a pink one at my last cottage and, after a few years it reached the top of our 3-storey cottage. I took seeds from it and one or two grew. When we moved from Cornwall to Scotland I brought a seedling with me, it has flowered this year for the first time after 12 years of growing. Be patient, but keep the plant trimmed back quite hard. My new tree has mauve flowers not pink as the original. Good luck, the perfume is worth waiting for!
I have a wisteria planted against a South facing wall, its been in my family for 15 years, I transferred it from my old house to my new house 14 years ago. It has failed year after year to flower. This year is no exception. I have pruned it back, each year. I do feed it and it is well watered. What else can I do?