Red Eyed might have a point in that it's not an autoflower, this happened to me with a Sweet Special, grew out 2, 1 auto flowered, but the other didn't, I culled mine, but it also happened to a fellow grower from the same seed batch, they flowered it on 12/12 and from what I remember, got a really good yield. If you do decide to switch to a 12/12 light to see if it induces flowering, it should only take 8 - 9 weeks to finish and as its already had effectively a 7 week veg, it might do you proud if it turns out to be photoperiod and not an auto