Translation:Die Jacke ist ihr zu klein.
They printed Das Jackett - haven't seen that before.
I'm guessing you used das Jacke, with the wrong article -- it should be die Jacke since the word Jacke is feminine.
"Das Jackett" is the jacket you wear in a suit. It is a possible translation though not really that plausible considering the context.
I hope I could be of help.