I'm confused, you're doing a degree, are you studying away at university? If you have the time to be a regular marine (as in move away for training etc) then you have time to be an officer. Both will require studying, research and increasing fitness for the application and selection process.
As for commissioning up to an officer, I'm not sure how the marines function but if it's anything like the RAF it is possible but VERY competitive and not the most ideal route.
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