A lot of people who chose to do eng lit at AS Level chose it because they enjoyed it at GCSE. In all honesty, AS lit will seem like a totally different subject to GCSE lit.
Only go into it if you really enjoy reading and writing essays. There are 4 or so books/plays you'll be reading, or more if you do AQA, plus lots of critical material, contextual books, and other books/plays written at the same time. The essays you'll be writing are quite hefty and they'll require a lot more analysis and flair than you're writing at GCSE. For the exams, you'll also have to memorise a lot of quotes, both from the books and from critics to back up your essays; also, in the exams you'll be writing maybe 2 essays in 1.5 hours? If you want, I can send you an example of an A grade essay for literature? There is a lot of work to be done for the exam, and so if you enjoy it I'd encourage you to take it, but I'll be honest when I say that if you're having doubts, it might not be the subject for you. Physics would suit your options much better, but 2 sciences and maths might be a little heavy, and I know plenty of people who study both English and maths.
What is it that you enjoy about english literature at GCSE?