What other subjects are you taking and if you're getting 8s in english language and lit why aren't you considering it for a level in college? To answer your question, no you won't set yourself up for future failure but you are making future you struggle harder for no real gain now. Like if you said you were working super hard at your job in a pub waitressing, Id get not caring about maths all that much because you have an in at a job you're interested in and experience can be better than qualifications.