Cardiff uni of uni of bath for astrophysics???

I firmed uni of bath this year and was accepted onto the course, but I'm having second thoughts and not sure whats best for me. I am a welsh student and I live about an hour away from cardiff, and about 3 hours from bath so a positive is that I will be closer to home. My main worry is the price of living in bath. While I do have max maintenance loan and will hopefully have a part time job, I know bath is known for being very expensive and would rather not have the added stress of trying to afford rent/food/social life especially after first year when I have to find my own accommodation. I'm very introverted and the thought of trying to find a house to share with people I've known for 2 months scares me. However, I know bath is better ranked for physics but it is not a russell group like cardiff. please give me any advice!!!!!