Bitcoin is 8.88 years old

The software has been running and the blockchain has been growing since January 3, 2009 at 2:15PM EST, when the genesis block was created.

The paper, Bitcoin: A Peer-to-Peer Electronic Cash System, was published on October 31, 2008 at 2:10PM EST.

The 3rd halving will be in 134,678 blocks, around June 13, 2020, and the block reward will be reduced from 12.5 to 6.25 bitcoins.