"There is a reason why you want to run a startup—much of everything else is the influence of societal pressures."
The problem is, you conflate reasonable doubts with irrational outside influences. It's not as if people who want to be entrepreneurs can't also want to get a law degree. Entrepreneurial ambition is not the only kind, and there are many legitimate reasons that a smart person might want to get a professional degree, aside from "society told me to do it".
The idea that you need to commit yourself wholly to whatever path you choose is well-taken, but the notion that you must eliminate all doubt in order to act decisively is excessive (and impossible).