Well, there was some numerical methods at A level. There was (for us) an iterative method for finding roots of equations, and one for approximating the solutions of definite integrals (a definite integral is the area under the curve on a graph, you won't have come across this yet but will in c2 of your A level if you go for that), although the word numerical method wouldn't have been mentioned at that point.
I can't say I've regretted it at all, I certainly wouldn't have been able to spend three years studying all of the interesting maths I would have done. I also went on a summer school with the London Mathematical Society, this was brilliant. I also wouldn't have been able to get onto the PhD course I chose, which I think will be really intersting. It is a lot of work and a lot of commitment, but really enjoyable (for me, but I'm a nerd
).
btw, is the name Matrix a reference to mathematics or the film? Associativity is actually a reference to group theory, from maths.