Maria Teresa was born in Milan to Pietro Agnesi, an overbearing man in the lesser nobility.
Maria Teresa was married to Pier Antonio Pinottini on 13 June 1752, and they settled in a district populated by intellects and artists, but eventually suffered severe financial ruin.
The movement was more prevalent in Vienna and Dresden rather than in her hometown of Milan, and Maria Teresa found more success and more appreciative audiences in these cities than in her birthplace.
He was not the only one; Count Gerolamo Riccati wrote several letters praising her compositions and musical talent.
Another very famous performance was her theatrical debut, the Cantata Pastorale Il Ristoro d'Arcadia, in Milan at the Teatro Regio Ducale in 1747 where she dedicated her piece to various rulers of the surrounding areas of Saxony and Austria.