The show has been under the spotlight after a war of words broke out between Bruce Forsyth and Cowell over children appearing on the show.
And Katie has sided with the 'Strictly Come Dancing' host, questioning if children are mentally strong enough to cope with the show.
Writing in her column in The Sun, she said: "Britain's children do have talent and I think it's great to see youngsters showcasing their skills.
"But are they mentally strong enough to handle the ups and downs of acceptance and rejection?
"The poor girl crying her eyes out for getting through was heart-warming, but how would she feel if this hadn't been the outcome?
"Come on, Simon, it's time to lift the age limit as high as your trousers," she added.
Judge David Walliams was the latest to speak out in defense of the show, stating that the only person who has broken down was singer Alice Fredenham, who failed to get through to the final on Tuesday night.
Simon Cowell and Bruce Forsyth
Taking to Twitter to air his views, he wrote: "#BGT is a huge opportunity to launch a a career, win a huge amount of money and perform before the Queen (Elizabeth not @SimonCowell ).
"The only contestant to go to pieces on this series of #BGT was Alice Fredenham. She is 28."
Child acts have stormed the live semi-finals, with four of the six act so far through to the final being younger than 15.
Which of this lot do you think is the best of the British Talent on display this year?