She had been learning the instrument for just six weeks when she played Mary Had A Little Lamb before a live audience in Plymouth, Devon.
Her music teacher Matej Lehocky said she was ‘bright’ and her talent was ‘unheard of’.
‘To play at her age is something extraordinary, something very special,’ he said.
‘Usually children that young are not able to control themselves or do what they are told.
‘Normally they just run down the keys and get bored.’
Mr Lehocky added she had shown great maturity for a person as young as her and although there were moments she would get distracted, she had something exceptional.
Neither of Lavinia’s parents, Ian and Jenna, who work as managers at a local Tesco, are musical.
Jenna, from Ivybridge, Devon, said: ‘I don’t know where Lavinia gets her brains from – she’s more intelligent than me.
‘Before she was two she could write numbers and letters and recognise them in books.
‘She told me what a trapezium was the other day; I didn’t know.
‘She seemed to be on the toy piano all the time so we asked her if she wanted to learn, and she said she would.’
Young Lavinia, who has just turned three, will be hoping she can fulfill her promise and title of ‘mini-Mozart’… no pressure then.
A video of her playing can be seen here