How are your traditional art skills? Life-drawing? colour? charcoals? watercolours? photography? any of that?
If so, maybe something like an Art & Design major (IADT perhaps?). Anything with a architectural / CAD component will assist your level design (IMO).
So if you dont have much in the way of an aesthetic eye, then I’d forget about modelling and so forth.
Learning the tools is something anyone can do – its the fundamental artistic aptitude that really allows a person to excel.
As for your "coding skills" being not up to scratch, well, your in secondary school, so there’s not much expectation there. Comp Sci will teach you everything you need and then some. If you have strong Math and/or Physics then your going to find this "native." (IMO).
right. That’s my 2 cents.