Believe me, GCSE's do not matter at all for degree choices at Uni. For example, I am currently in year 13 (upper Sixth Form), and in year 10 I wanted to be an Animator when I was older, so I chose to do Art. I was actually rubbish at Art, getting basically E's/U's in the subject (though I managed to get a C in the end), though I was foolish enough to think that it would effect me getting a degree in Animation.
Now that I am at the point where I am applying to Uni's and bringing in offers, 3 years later. I've learnt that it's your A-levels that influence everything, they only glance at GCSE's to see how well you did grade-wise, to whether you passed english/maths.
Besides, Science is compulsory for GCSE, so as long as you pass that, as well as maths and english. I wouldn't worry about your future career/degree until you hit A-levels ! Though it is always a good idea to think about the sort of field you want to be in when you older. I changed my career/degree choice by Year 13, and I'm sure you'll either change completely, or go for a degree/career in the science field ! (: