Bitcoin is 15.55 years old.
Bitcoin's genesis block has a timestamp from January 3, 2009 at 2:15PM EST.

The block included the text "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks".

The second block's timestamp was January 8, 2009 at 9:54PM EST.

The domain was registered on August 18, 2008 at 9:19AM EST.
The paper, Bitcoin: A Peer-to-Peer Electronic Cash System, was published on October 31, 2008 at 2:10PM EST.

The 5th halving will be in 196,451 blocks, around Monday, April 17, 2028, and the block reward will be reduced from 3.125 to 1.5625 bitcoins.

"I'm sure that in 20 years there will either be very large transaction volume or no volume."

Satoshi Nakamoto