Was the little red headed girl that Daniel Faraday saw in the Barracks in 1974 really Charlotte? If so that would be 5 years before she was meant to have been born in Kent.
If so did she leave the Island 'donkey wheel stylie' a few years into the future and would have corrected her apparent age to that of someone born in 1979. Or was the little girl someone else completely different and poor old Dan is just tripping out.