Did/do you worry about potentially picking the wrong career?
I went from studies to become a pastor...to working as a cop...draftsman...truck driver....and now I'm an RN. I am 50 now...it's been a confusing and expensive journey.
The whole problem is that I don't know what I want to do
Not at all. I trusted the right career would find me, and it did. Careers aren't tattoos. You can easily change to another if the first path you chose proves less than you'd hoped.