GCSEs

They are only really important for getting into college/sixth form and otherwise would only be looked at by Oxbridge, even then they are not that relevant. Once you have been accepted into college/sixth form, that is basically their usefulness unless you were going to apply for a lower level job, who would look at your GSCEs. It is still important that you do your best just in case of any future opportunities, but as long as you work really hard at A-Level and get good grades then, they will have a much higher priority over GSCEs for university/career options. Please don't stress too much now. Hope this helps!