OP I don't think it's anyone's business, including your mothers, once you're paying your way, not getting into debt and not asking her for money.
There are some right misery guts on the Christmas threads on here and some incredibly sanctimonious and judgemental poster.
I can never get over those who can afford to buy their children presents but chose not to...
Anyway, we have a teen and have spent considerably more than £600 on her this Christmas and we have always bought lovely presents for her. We buy quality over quantity and always have done. And I really don't give a fig what anyone else thinks.
We own our own home and have done since before we had dd. we have a comfortable lifestyle and savings for us and her. So we spend what we like on her Christmas presents and she is not spoilt and rarely asks for anything. We also buy her things throughout the year as she needs them such as clothes, makeup and trainers etc
Life is hard so much of the time, it makes us all happy to give each other lovely gifts once a year.
Even in times when money was tighter (when we were younger) we always prioritised spoiling each other a little bit with a thoughtful (not always expensive) present and making a fuss of each other. wee learnt long ago that no-one else will do it and it's SO easy to lose that side of things in a long term marriage / relationship where it all becomes a bit of a drudge and you no longer see each other as the individuals who found each other remarkable! So...we make the effort and we make the effort for dd too.
She has a tv and apple tv for her room as her main present and then lots of hard to find quirky things that reflect her interests which she will not be expecting.
We can't wait!
OP - hope your dd loves all her gorgeous presents