I suppose that if she falsely testified about her occupation in order to try to get off (or a lighter sentence), that is perjury? Courts take a dimmer view of that than killing cyclists...
Giving false evidence is perjury, which people are sometimes charged with.
If you think about it, perjury happens all the time at a trial.
Person A says one thing, Person B says the opposite - both cannot be true so someone is lying, and usually wilfully so rather than being honestly mistaken.
But in this case it's a red herring, she will be a carer if that's what she said she was.
Something else that doesn't really matter, but in the interests of accuracy: 'carer' is capable of different meanings.
I've used the the term 'occupation', but I don't know that, when she said 'carer' to the jury she may have meant she's a carer for an elderly relative.