She was last seen in St Pauls Avenue around 8 p.m. last night (14/6).
Steffany is believed to be dressed in black shorts and a white tank top.
Steffany has been seen in the park near Bower Recreational Ground and other open green spaces.
We are very concerned for Steffany’s welfare and are appealing for the public’s assistance in finding her,” said Sergeant Aaron Sinclair-Day, based at Slough police station.
“I would ask anyone who has seen Steffany or has any information about her whereabouts to please contact us by calling 999.”