Quite. The previous history is irrelevant to the particular trial taking place. It is the job of the crown (or DA, or whatever) to prove guilt for the crime the defendant is being charged with, not for something they did in the past.
The UK and US court system is very similar, for obvious reasons, but there are a few differences. For example we don't have jury selection in the same way as the Americans do. PanAm747, head up to Canada - they've got the same (more or less) system we have.
She's as nervous as a very small nun at a penguin shoot.