You're right; Jesus Himself warned us against making wild guesses about His return or claiming to know exactly when it will take place. He said, "Therefore keep watch, because you do not know on what day your Lord will come" (Matthew 24:42).
But Jesus did tell us two very important truths we must never forget. First, He clearly taught that some day He will return. Unlike His first coming, His second coming will be glorious, and all the earth will witness it. He said, "When the Son of Man comes in his glory, and all the angels with him ... all the nations will be gathered before him" (Matthew 25:31-32). When He comes again, He will rule in power and justice, and He will be victorious over all evil.
The second truth Jesus told us is that certain signs or events would take place to indicate that His coming was near. I believe we see many of these today. For example, He said that the Gospel must first be preached to the whole world, and only then would the end come (see Matthew 24:14). We see this happening today. Yes, Christ could return at any moment!
The real question, however, is this: Are you ready for Christ's return? You can be, by asking Christ to come into your life and trusting Him alone for your salvation. Make sure of your commitment to Him today.