If you take any hard science/math subject, in my opinion, your marks are in your hands. If you perform exceptionally well at those subjects you will (Microsoft) excel in CSS.
If you do not have a background in these subjects (no formal education, only an 'interest') then I would stay away from them.
Opinions may differ, however, since I have a background of Pure sciences, Social Sciences and then eventually business, I believe I have a general idea regarding this pickle of a situation.
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