As Marcus Lemonis often says: there are 3 Ps: "People, Process, Product".
And would add, in that order and the first P = People is the most important.
The number of startups that pivot is uncountable, and process can be changed as well. But not the people.
Ask yourself -are they trust worthy not only in leading the company to the right place? Will they share information with you after you invest or will they make sure to make all the decisions alone?
I've seen great ideas falling apart in the hands of the wrong people, so make sure that the team in this company is right for you, right for the product and right for the market.