Littleone,
Welcome to the board. If you want, you can do a mini-bio about who you are in the "Make New Friends" forum.
One quick technical note, you ARE able to go back and edit a mistake in your post (such as where the word "Gospels" appears) by clicking on the "pencil" icon just above your post, and then over-typing the error you want to fix.
As far as prophecies always being revealed BEFORE they happen, I'd like to point to a specific example and get your thought. That is, the 1914 prophecy of C.T. Russell and the early Bible Students. At first they thought 1914 would mean the end of earthly governments and their being raised to heaven, which of course didn't happen. In 1925, the "understanding" came out that what REALLY happened in 1914 was that the Kingdom Government was established invisibly, in heaven.
So the prophecy didn't get fully understood (if indeed the 2nd guess was even correct) until over a decade later.
So the "faithful slave" seems to acknowledge that prophecy is not fully complete until AFTER the event.
Unless...this is where the question to you comes in, was this really a prophecy at all? Your 2 requirements in your post were (1) It's mentioned in the Hebrew Scriptures and (2) it is somehow confirmed (made "Amen" or "yes") by Jesus at the time he walked the earth. So really does the 1914 "prophecy" fulfill those 2 requirements?
And where does the WT Society stand in relation as a reliable indicator of Bible prophecy?
Gopher