Unless you have a newer variety of gardenia that is known to be a repeat bloomer, (the variety 'August Beauty' is one example) most gardenias only bloom in the springtime, usually April through May here in Florida. You're fairly similar in climate to us, I think. But we didn't have any frost last winter at all. If yours is a regular spring bloomer, yes it would be in full growth mode now and I wouldn't consider pruning it at all. You'll cut off the new growth that will bloom next spring.
If you had a cold spring or a late frost, that certainly could destroy the developing buds, or at least make the bushes slow down and bloom later. Watch your weather forecasts and cover those bushes on the cold nights if you get the chance, next winter.