Educational and Career Advice - Overwhelmed by my Freedom of Choice

I've just finished my BSc in CS at a respected UK university - expecting to get either an Upper-Second Class or First-Class Honors - and the opportunity arose for me to do a 6-month internship in my home-country in the Corporate Derivatives Sales division of the leading investment bank.

I had been a bit discouraged by the area I would be joining, as the consensus on this website is that there are few exit-ops from this role and it certainly is not nearly as prestigious as other areas. However, I'm a few months into the internship and it's been the perfect introduction to working in finance, as I've been broadly exposed to the different areas - because there's always risk to hedge, whether in a bond emission or a debt-financed acquisition - and I've been learning the fundamental mechanisms behind each area as I participate in different transactions. I've focused on learning derivatives math, automating all business processes I can, and now attempting to open new lines of business for my desk.

I'm now certain I want to stay in the world of finance, using my technical background to supplement whatever work I do. I started studying for the GMAT, and I'm aiming to achieve a 730+ by the beginning of next year. At this stage I'm just overwhelmed about all my options. I don't know whether I should aim for a Masters in Finance, Financial Engineering, Economics and Finance (or Econometrics), or go straight to an MBA? And where do I want to go after? I could do IB, PE, Consulting (in a banking / finance group); and within these specific career paths there are so many other choices of specialty, whether it be Tech M&A, REIB, REPE, and so on. Maybe I should've prefaced that I've always been entrepreneurial, and I run three positively cash-flowing businesses with friends on the side, but the fact that I've always valued being a generalist and now have to choose something to start specialising in means I'm "closing" so many other doors. 

The pieces of this puzzle that are clear in my head are the following: I'll be using the technical and programming skills I learned in my bachelors to supplement whatever finance related work I do (even if not explicitly required), I'm set on doing my Masters in Europe and if so would like to shoot my shot at an M7 MBA post-experience, with the eventual end-goal being setting up something of my own (PE, VC, etc.), hopefully with my current friends and business partners who also intend to follow a career in finance. 

I'd like to hear what those of you who've been where I am now - possibly with a similar unusual STEM background - did, and how you reflect on the choices you made. Thank you in advance.