Hey there. Within Catholic understanding, nobody really knows. It could be tomorrow or it could be 5,000 years from now. Personally, I think it is going to be soon (how soon, I don’t know). I base this thought upon the hatred and wrongness of our society and the world. Look at all the horrible and unjust wars, the people starving because nobody helps them, abject poverty, unnecessary greed, dictatorships, immorality in culture, depraved and scandalous clergy, heretics in the Church, etc. Also, there are many prophecies from various saints throughout the ages. In the link on my signature, Our Lady made very significant predictions which seem to be playing out now (though they could really be intended for a later date).