Can anyone help me?

I tried to apply to Cambridge a couple of years ago when I did my A-Levels and Further Maths is almost a necessity. When I got my application feedback they explicitly said that over 80% of their applicants do A-Level Further Maths. So even though they say that FM is encouraged, I would argue that based on these statistics and based on the competitiveness of such places FM is almost a necessity.

That being said, you have strong predicted grades and study physics and maths which are absolutely necessary for this course and you would likely meet their minimum requirements. Therefore, I would encourage you to have a go and apply. I think that it's too late to do AS Further Maths, but you can still do it to prepare for university, because a lot of aspects of an engineering degree will cover Further Maths content anyway. It'll be slightly easier if you can at least familiarize yourself with AS Further Maths content. I think you should have a go, but don't put all of your hopes into this because Engineering at Cambridge is incredibly competitive. The acceptance rate for an engineering course at Cambridge is approximately 15% to 20%. That's about 1 in 5 applicants getting a place.

Yeah, thanks a lot for the help.
This is what I thought it would be, I might as well give it a go, I will have 4 other options anyway. So do you think I should try to take an AS in it and get a grade or just learn some of the content? Because I was doing an ENGAA past paper with my mate who is doing FM and there was a question on the sum of roots of a quadratic, which apparently is only taught in FM(it's simple just -b/a but I would never have known this before doing the ENGAA without FM, although by revising I still probably would have found it but still, that's an example I can think of).

Yeah, thanks a lot for the help.
This is what I thought it would be, I might as well give it a go, I will have 4 other options anyway. So do you think I should try to take an AS in it and get a grade or just learn some of the content? Because I was doing an ENGAA past paper with my mate who is doing FM and there was a question on the sum of roots of a quadratic, which apparently is only taught in FM(it's simple just -b/a but I would never have known this before doing the ENGAA without FM, although by revising I still probably would have found it but still, that's an example I can think of).

I would say probably learn some of the content. I think that there's no point getting a grade in AS Further Maths if you're not actually planning to take a full A-Level in Further Maths. I think that it might be more beneficial for you to just learn some of the content. You don't need all of the content anyway, there's only specific parts that you need to focus on. I studied an Engineering degree at uni and I would say that the most useful FM topics would be these:

Complex numbers - This was used everywhere in my electronics module and it's absolutely essential
Matrices / Linear algebra - I am shocked that this was not covered in A-Level maths and physics, because this is absolutely essential when solving linear or differential equations using computational methods and forms the basis of everything that you will do later.
Second order differential equations - This is also particularly useful because you will very likely come across the damping factor and natural frequency throughout your time at uni. It's important that you know how to solve these.
Taylor Series - This popped up in my uni lectures from time to time. A useful thing to know.
Mechanics - And of course this is a big one because we are engineers and therefore we will need to have a good understanding of things like momentum etc. The more mechanics you self-study the better.

I think these are probably the most essential FM modules that overlap with university first year content and would be very useful to know and understand. As far as I can remember, ENGAA shouldn't include any Further Maths content. It should be completely doable for students who only take A-Level maths and A-Level physics. However, this does not mean that it's going to be easy by any means. I remember when I sat my ENGAA and absolutely flopped it because the questions were incredibly tricky and hard. The reason they were so difficult is because the questions were very wordy and long and I only had a limited time to think about a solution. It wasn't because it had content I haven't seen before. For this assessment, A-Level maths and physics should be enough.

For the sum of roots part, you really do this at gcse for basic quadratic factorizing. It may not be emphasised, but ... Similarly c/a is the product of the roots. Rather than being a further topic, its more about asking a question in a slighly unusual way which is what the entrance exams typically do.

This is really helpful, thanks. If I was to try to learn some of the content, would it be a good idea to mention something about that in my personal statement? Or is that unnecessary, as they don't require FM?

Absolutely. As far as I can remember, when I first applied to university, I wrote in my personal statement that I was self-studying further maths and that was fine. You will come across A-Level further maths content at university because there is a lot of overlap, so you will have to learn it anyway. If you write that you self study further maths then you will show that you are serious about the degree and that you are preparing yourself for it and that's never a bad thing.

Would agree with all of the above, and also add that at Cambridge, they don't assume Further Maths content, so they will teach the things from further maths that you need for the course, but they will do it at a really high speed, because they know that most students will have done it before - if you do end up going, it'll really help for you to go over some further maths concepts.