Mrs Oldham holds the world record for the oldest women to cross the channel and said this time she felt much fitter.
‘I have put a lot of time and effort into it,’ she said.
Mrs Oldham began her preparation after her second shoulder reconstruction.
‘As soon as I could swim, even if it was one arm, I started to train,’ she said.
Mrs Oldham, who did not start swimming until she was 48, said she was well prepared.
She trains six days a week in the pool, alongside physiotherapy and gym workouts and ocean and river swims.
‘My coach, Paul Newsome, has been very supportive and influential in improving my stroke,’ she said.
‘However the bottom line is that without all this hard work you can put your life at risk.’
Mrs Oldham flies to England on July 23 where she has an eight-day window to complete the swim.
‘Many attempt the swim and can’t finish ” you can get a good run or you may not,’ she said.