Yep, it's been 18 years...
Soon I will reach that age too, I've been with One Piece my whole entire life. Although discovering it was a bit later I can truly say One Piece is been going on for my whole entire life...
To celebrate I'll get a cup of sake (oh wait yeah not 18 yet, guess I'll get some orange juice then, young Luffy loved it anyways) and read romance dawn again.
From the first moment I graced eyes on that color cover, with a jumping Luffy and Nami and the red hair pirates cheering about, I just knew I was going to go into something that would change my life completely.
So yeah, One Piece can now get a driver licence! And drink!
Right now One Piece is as old as Luffy was after Strong World (although it's not really clear, let's not start an age war)
Oda says about 9-10 more years so it'll be arround 27-28 years. Wow... time sure passes by.
Happy birthday One Piece!