I'v been told alot of diffrent time frames. I heard a year before any corals to right after it cycled. I personally had corals in my tank with in a month of it being set up. But elagence corals are very sensitive. I know many of people who have alot of bad luck with them. I do believe they need a mature tank(6 to 7 months) to really thrive.
I agree with what has been said above. You also may want to try some easier corals like mushrooms, a toadstool or a colt. These will probably do fine in your tank now, given you have propper lighting. HTH