If it was a murder conviction then "life becomes life", the judge said.
Police prosecutor Sergeant Nick Newbery said that on March 15 Shergold entered a store in Auckland and while the shop assistant was serving a customer he approached her and "grabbed her by the bottom with the palm of his hand".
Shergold had then left the store and stood outside, staring through the window at the woman until police officers arrived, Mr Newbery said.
"He claimed he didn't know why he did it."
Judge Mill remanded Shergold on bail for a pre-sentence report and sentencing on June 26.
Meanwhile, a 49-year-old Wairarapa man known to his 5-year-old victim as "Uncle Fish", although not related to her, has also been served a first-strike warning for indecently assaulting the young girl.
Darron John Fisher, now of Titahi Bay, pleaded guilty to two counts of indecent assault.
Lawyer Ian Hard said that, while Fisher admitted the assaults, he denied any attempt to have photographs taken.
Prosecutor, Mr Newbery said Fisher had been best friends with the victim's father for about 30 years and the girl and her 8-year-old brother would call him "Uncle Fish".
In January, he stayed weekends with the family helping his friend to paint the house, looking after the children about a half a dozen times.
On March 15, Fisher was babysitting the children while their parents went to a birthday party.
Twice throughout the early evening he enticed the girl to play games including playing nurse and a dart game with the losing party having to pull down their pants.
Mr Newbery said the victim's brother interrupted the games and was asked to take photographs. The boy witnessed some of the abuse, he told the court.
"At one stage the brother knocked on the [bathroom] door and [Fisher] yelled at him to get out."
Judge Mill remanded Fisher on bail for a pre-sentence report and sentencing on July 24.