Computer Science A Level Coursework

Going into year 12 computer science and only have GCSE python knowledge, is this enough to start coursework immediately?

Nope. Absolutely not. To give you an analogy, you are basically going into a driving test without knowing how to turn on the engine.
1) Do NOT start it now. You don't know the first thing about the NEA and the stuff you need to do for it. To get top marks in it, you need to understand and learn the programming concepts they first teach you at A level because that is what fetches you the marks.
2) There is no way that GCSE level Python will suffice. There's a reason NEA is done in your A level year and not at GCSE. They announce the project in Jan of Year 12 onwards and then you have until Feb of Year 13 to return it (some schools give you even more time but my school asked it in for Feb) so time isn't the problem.
3) Why are you starting it now? You have ample time to complete it and you should spend the remaining few days of your summer enjoying it as much as you can. Trust me, GCSE is the best summer holidays you'll ever have. The one after A levels just isn't as fun because you're sat there stressing about whether you've done good enough to meet your university's requirements.
4) Don't go into the NEA with a narrow mindset. This is your chance to expand your knowledge base. Maybe choose to do it in another programming language like Swift, or Java, or Javascript, or Unity or C++? The world is your oyster with the NEA. But first, and I really can't stress this enough, WAIT FOR YOUR TEACHERS TO TEACH YOU THE PROGRAMMING BASICS REQUIRED FIRST AT A LEVEL BEFORE YOU GO INTO THE NEA.
You need a basic skills framework first before you go into it, and if you ask me, the skills required for the NEA often go above and beyond A level standard (at least, this was a common occurrence in my set).

Going into year 12 computer science and only have GCSE python knowledge, is this enough to start coursework immediately?