Almost certainly too young. They can and often do flower as quite small plants, but not invariably so. Right now the most important consideration is that the plant is healthy and growing well, although it will eventually outgrow even the largest container.

Have you pruned it at all, and if so when? The tub its growing in should be 12 - 18 inches deep by 16 inches wide as a minimum. Are you feeding it and if so, what with and how often?

Mine flowered this year, in its second year after planting, but only produced a few flowers. I'd be patient and hopefully next year it should flower.