What should I do about my current situation?

Hey everybody, so im first year university right taking 2x economics courses, calculus, and philosophy. I came into university wanting an economics degree(didnt think about it, just decided) so it was a rash decision. I always wanted to be a mechanic(am good at fixing cars, have made a lot of money restoring vintage cars) but just went to university because my parents wanted me to. My mom has been suggesting a couple of times that i go to a trades school to learn a trade because she knows im not really the kind of guy that likes studying. Fact is she doesnt know i wanna be a mechanic. Should I just come out and tell her? Also I am failing both my econs(missed a midterm), possibly failing math and doing good in philosophy. I just want one more semester at my current school to learn history(always loved it). What do you think I should do guys? I know it doesnt really matter that I fail all my courses because they dont count for trades school but I just feel bad about wasting money and not trying hard and all that.