Maternity leave advice


Hello, I was wondering if someone could give me some useful advice, I'm 20 (soon to be 21) and I'm 16 weeks pregnant (first child) I've been working part time in retail for 10 months now (I hate it but it's a job so I get on with it) I've found out that I'll be entitled to maternity pay, and the earliest I can take this is 4th November and I have to let me employee know that I'm leaving by the 13th October. I'm also a university student but decided I'm going to take a gap year between my second and third year as there is no way I could complete my third year with a new baby (I'm just assuming this as I couldn't possibly know - however baby is due in January when all my first Semister exams will be). During the year out I will be looking after baby while my husband (yes I got married very young) will work full time however as I want to get into medical school I plan on volunteering in a hospital for my experience when my husband isn't at work so he can look after baby. I do NOT plan on going back to work at the retail place I'm currently working at, do I take the earliest possible leave from work and use that time to relax and get things planned for the arrival of baby (2 months) or do I take my leave later giving me 1 month before baby arrives ??