How long have you had it? It can take 2-3 years to go from a small plant to start fruiting. If it's about 3ft tall from base leaf to crown, it should be ready to flower. Base leaf is the leaf closest to the soil, crown is the center point where the leaves come out.
I never needed to do ethylene to get fruiting on my pineapples when I was growing them. It'll flower when it's ready. It needs to store a certain amount of resources before it fruits. Once it has enough, you can't stop it.
Here are some ideas:
In late spring, start giving it some flower fertilizer--by which I mean something marketed for flowers. In the NPK numbers, you want something with a low first number and high middle number, eg 5-50-17, or 5-30-12, or 1-10-4. Numbers will vary depending on what's available to you.
If you find something water soluble, even better. You can dilute to 15-20% recommended dosage and pour down the crown leaves. Let it flow down. Be careful not to let the center become water logged...if you water in the evening, it should be warm enough that the water evaporates out at the end of the next day.
And then mid-summer, cut down on watering. Enough so the top 2-3 inches are dry, but still slightly moist under that. This will stress it out and it'll trigger flowering. It needs a consistent minimum day temperature somewhere in the mid-80s F and plenty of sun.
If you get lucky, you'll see the center grow its special flower stalk.
I don't grow pineapples anymore. 2 years of growing only to get one pineapple per plant uses up more time and space than it's worth for me. It is unique though, and very few people outside of the growing regions can claim to have seen pineapple flowers up close.
Good luck!
