Betty and Jenny live near each other and have planned to mark their century with a holiday in Budapest, Hungary.
'We never think about our age much - it's other people that make the fuss,' The Sun quoted Jenny, as saying.
Betty added: 'Life is much faster now but the only thing I don't understand is computers.'
The sisters were born in Manchester in a different age; the doctor arriving on horseback to deliver them.
Betty said: 'I remember seeing two small planes in World War One. I ran in screaming and got under the table.' Later the family lived in Kent.
Both the sisters are now widowed and live in Feock, near Truro, Cornwall.
When asked the secret of a long life, Jenny said: 'Keep smiling and keep going.'
Betty joked: 'And keep breathing.'