Will I be prosecuted for illegally (unknowingly) downloading torrent files in the past?

I used to download torrents for movies, games, etc. in the past and really DID NOT REALIZE that it was illegal, due to my ignorance and stupidity. (It was so damn easy, I thought piracy took like an advanced computer hacker or something and thus it must be legal...STUPID I know...) I stopped as soon as I found out the truth. My question is, is it already too late? Can I be unfairly prosecuted, fined, arrested, etc. for my admittedly stupid yet perfectly honest mistake? (like get a letter several years after the fact summoning me to court or something...) I am VERY concerned and a bit scared...