Well, there's probably a few people my age who can outrank me as a Beatles fan, because it was a few months after Love Me Do had already been in the charts (low down in the top 20) that I heard them at all. But I was a die-hard fan by Christmas 1963, and was playing their stuff on my guitar. So I'll guess early to mid-1963. Not quite 46 years. There might be some Liverpudlians or Hamburgers(!) who can claim up to 49 years, if we stick strictly to when "The Beatles" was the name of the band. But since John and Paul used to practise and compose quite often at Paul's house, we might guess Mike McCartney was the first Beatles fan. (Question is: was Paul a Scaffold fan?)