"I became quiet immediately."

Translation: Eu am tăcut imediat.

[Euratos]

Are you sure it isn't "M-am tăcut imediat."?

[Dodorynde]

Yes, "a tace" is not a reflexive verb

[Dorin4926]

eu am devenit imediat linistit... varianta B...

[Dodorynde]

The correct translation would be 'Am devenit tăcut imediat'. 'Eu am tăcut imediat' would be 'I shut up immediately'.