Hi Heston,
Interesting name, never heard it before
I love martial arts movies myself, last one I watched was "Confessions of a pit fighter" quite good, and more realistic which I prefer.
The problem with movies is that things are always so good and go so smooth and may give you false representations of real fighting, it is alot different let me tell you.
I just used a converter to convert stone to kg as I had no idea, its about 66kg/145lbs. You are quite small and i'd be irresponsible if I said "size doesn't matter". It has been said, but I believe that size and strength does matter.. like if you have 2 equally skilled people the bigger and stronger one will win.
BUT there is things you can do things to compensate. Good training physical and your mindset and psychology. If you have some good training then you will be able to handle it.
I don't really have the same problem with size as I am about 105kg/232lbs. But because of my training I have been able to take out people bigger than me, even back when I was about 10kg lighter. If I didn't have my training, I would have got smashed a long time ago, but I have managed to keep myself safe in a risky environment. (Working in a bar).
Also the most important thing that comes first is awareness/observation/avoidance.. if you know something is coming and can avoid or have pre-warning, it helps.
And the other big thing is just learning to handle the fear and stay more calm in threatening situations. Because if you can't handle the inherent fear, you can't act effectively.
As for training, look at Richies main site, www.streetfightsecrets.com
I recommend the cd's "Psychology of violence" highly for your mindset and dealing with fear.
And also look for the link "Beta-8 dvds" and purchase the pack of 3 dvd's. That will give you a very good base, because you have no experience, that is the best way for you to go.
-Ben