Let’s start with what you do NOT need:
Accounting
You are not really tracking inventories, sales, costs, tax regulations, etc, for clients so, no.
Politics
Machievelli, Locke, Hobbes and Jefferson are interesting but…
Communication
You can type, you can communicate.
Management
Who the heck are you managing when you are trading your own account?
That leaves – economics and finance.
As for finance, you are not borrowing and lending or “financing” so it is not really applicable.
Four years of economics to study “Supply and Demand” is a bit excessive. It can be summed up in a few short sentences.
Dude/Dudette,
Study whatever you are drawn to, whether it is economics, politics, veterinary medicine or modern dance… NOT what you think applies to the very limited applications of these areas of study that may apply to forex trading a personal account (or even institutional account – they will teach you what you need to know so find out what THEY are looking for if that is what you are seeking).
In the words of a stupid song from a few decades ago – “Don’t worry. Be happy.” Do whatever turns you on and makes you happy. Otherwise, you are pidgeon-holing yourself into a life of misery. I’ve already made that mistake once and I won’t do it again but that is another story…
Finally, never take life advice from anyone on the internet:D