Close to five years. I knew about bitcoin and was slightly interested, I bought 3 BTC and just held it. After I year, I realised I had three bitcoin and sold at $1200 - Just before the crash.
Only early last year was when I got really interested with bitcoin, however.
That's mean you have a missed the chance to be millionaire at that time, too bad you only collect 3 btc but it's okay i think we all have another chance with bitcoin.