The biggest career mistake I made was to choose engineering after 2nd PUC. The only reason I took up engineering is because all my friends opted it as a career option. What followed was a chain of mistakes.
After mugging up textbooks for 4 years, I realized that I didn't want to take it up as a career, but I was offered a software developer role in a service oriented company and I got carried away. I took the job offer and worked there for 2 years and after hating the job, I finally decided to quit and shift to the Finance sector.
Currently I'm studying for the CFA exams and honestly I'm finding it a bit hard, but Finance interests me and I don't mind putting in an effort, because I know I will enjoy working as an accountant.
My advice to anyone who is confused about their career and don't know which field to choose, I suggest you take some time and find what you're interested in and only then decide a career for yourself. Because at the end, you'll be spending over 9hrs, every single day at work and if you dislike your work, you will not be content and happy with yourself. So make sure you choose a career that aligns with your interests.