In chapter 2 of Acts ,this is the seen of Pentecost and the speaking of tongues. People started freaking out thinking these people are drunk an Peter gets up and says in verses 16-17 these people are not drunk this in the fulfilment of the prophecy written in Joel. He goes on to describe all these things and those accomplishes by Jesus and says these are the last days. He goes on then in verse 40 mention this all and about this evil generation.
Read chapter 2 and you to will see that the writer of Acts was stating that the last days and the this generation was then.