Try not to panic! Don't listen to your Mum because shes feeding you unnecessary stress and causing you to worry even more and about something that is more than a year away. Trust me, the universities will mostly look at your personal statement, your AS level grades and the grades your teacher predicts you at A2. Law may be a little different than other courses, but I've heard the only reason they would look at your GCSE grades is because of a high amount of competition for the course and they need to look more in depth into each student, but I'm not sure if that's true. One of my friends got an offer for Durham and she didn't even have GCSEs or an equivalent in a different language! When the time comes, I would honestly focus on your personal statement and really try hard for this years AS exams and year 12 is not the year to slack off, it counts as much as year 13 regardless of what other people think. And if you're from the UK, try to get some sleep and don't think this too much, in AS I achieved much lower than I expected and by staying up worrying I wasn't doing myself any favours and just adding to the stress. btw, congrats! I think they're great results!