Even Diana took years in the job before growing into the global icon who was so admired before she was taken from us so tragically.
For somebody who is relatively new to royal engagements, Kate has performed with aplomb.
On foreign assignments too, I have seen her at close quarters in Canada, America, Singapore and Borneo. She is professional and warm, complimenting her husband Prince William as they carry out their royal duties together.
Kate and William are a great double act. There is her wifely strength, like the Queen Mother, and as a Queen Consort she does not try to steal the limelight from her husband.
The Palace and Kate have kept a dignified silence over Mantel's rant. It's a wise stance.
I know the team around Kate and far from her being a "machine-made doll" or "designed by a committee" she has a hands-on role in everything she does. They follow her lead.
She has chosen to be patron of charities in which she has a deep personal interest.
Kate, in the coming months and years, will let her actions speak for her.
Today she was back doing royal duties for her charity Action on Addiction at Hope House in Clapham, South London.
She looked fabulous as she stepped out of the royal car, happy to show her baby bump to the media gathered outside. She was well briefed and knew her stuff.