Hebrews 1 identifies the "last days" as already began when this text was written;
1 In the past God spoke to our forefathers through the prophets at many times and in various ways, 2 but in these last days he has spoken to us by his Son, whom he appointed heir of all things, and through whom he made the universe.
The last days includes the first century, our currernt time period and the time up until the 2nd coming of Christ.
The point of Matthew 24 is to show that during this entire time period of last days, however long they may be, we would continue to live in a world filled with uncertainty including, strifes, wars, earthquakes, false prophets, persecution of the church, etc. but we (the church) need not to be overly concerned with these things so as to loose faith in God. For these things are only temporary and the clock has already started ticking towards the end, at which time God's promise of the "new heaven, and new earth" we are awaiting, will be realized. He who endures, in the faith, until the end is saved. Peace, Lilly