The Duchess - due to turn 75 on July 17 – went on to say she loves getting texts from her five grandchildren, all of whom are aged between 12 and 14.
She added: "It's very nice getting a text. We learn from very young people and they learn from us, too. That's the way it's always been."
The Duchess also disclosed that her grandchildren had unsuccessfully tried to convince her to get her ears pierced.
She described watching her granddaughters "beginning to get into clothes and makeup" as "rather frightening" – adding: "You see them coming out with pierced ears and a lot of new makeup and funny-coloured hair and stuff."
While preparing for her Vogue shoot, the magazine's team proposed she wear an outfit matching the wisteria in the garden at Clarence House.
The idea was immediately snubbed by the Duchess who has called the colour "menopausal mauve".
She instead opted for an evening dress by Bruce Oldfield Couture from her own wardrobe, saying at the shoot: "I did have some (press-on) nails, but I lost them all gardening yesterday."
She also told how she and her and husband the Duke of Cornwall, 73, attempt to make time for each other.
Camilla added about her relationship with Prince Charles: "Sometimes it's like ships passing in the night, but we always sit down together and have a cup of tea and discuss the day.
"When we go away, the nicest thing is that we actually sit and read our books in different corners of the same room.
"It's very relaxing because you know you don't have to make conversation. You just sit and be together."
And she revealed how negative public reaction to her relationship with the Prince of Wales in the wake of his split with Princess Diana was a challenge, admitting: "I was scrutinised for such a long time that you just have to find a way to live with it.
"Nobody likes to be looked at all the time and, you know, criticised and... but I think in the end, I sort of rise above it and get on with it."
