My mum has had a koi pond for about 12 years or more, but I have never really took a huge interest in it. I have always enjoyed looking at the fish, though.
As for fishkeeping myself - my eldest son kept badgering me for a small tank for his bedroom about 2 years ago. I relented eventually, and now we are on our third tank, and it is now down in the lounge. I think you can safety say that my son is responsible for my getting into fishkeeping.