Am I finished?

I’m in yr12 currently at a good sixth and my UCAS predicted grade is CCC, I’m not smart naturally but and I messed about for the first two terms of sixth form. I do maths, physics and history and want ABB in my final grade is that realistic to achieve or not? I got DDD in my mocks in Easter and it was my first time revising for exams as I did basically nothing for GCSE’s and my revision technique was very poor. I’m prepared to put the work in as I want to go to a good uni with my preference being Newcastle or Exeter. I resiting my mocks in all my subjects after summer and was hoping for BCC in them so hopefully so I could be pushed up to ABB for my predicted. What work should i be doing over summer and how much to get the grades I want?
Am I cooked or do I still have time?

I’m in yr12 currently at a good sixth and my UCAS predicted grade is CCC, I’m not smart naturally but and I messed about for the first two terms of sixth form. I do maths, physics and history and want ABB in my final grade is that realistic to achieve or not? I got DDD in my mocks in Easter and it was my first time revising for exams as I did basically nothing for GCSE’s and my revision technique was very poor. I’m prepared to put the work in as I want to go to a good uni with my preference being Newcastle or Exeter. I resiting my mocks in all my subjects after summer and was hoping for BCC in them so hopefully so I could be pushed up to ABB for my predicted. What work should i be doing over summer and how much to get the grades I want?
Am I cooked or do I still have time?

You need to speak to relevant teachers and ask for their advice - and then you need to do some work over the summer, and that's really work, not just playing at it.