I find that the students who have a true interest in learning to fly, for the sake of learning to fly tend to show better aptitude v.s. the ones who are focused on the airline career that's still years down the road.

Also, keep in mind, that you will be earning your certificates and ratings in stages. After you receive your private pilot certificate, you'll be in a better position to evaluate whether you want to take things to the next step.

Food for thought, these instructors that you've done your intro flights with might not be blowing smoke up your arse. Given the fact that you've done several discovery flights you might just be less of a "deer in headlights" than they would expect from someone who's never done a discovery flight before. I.E. you're more comfortable in the airplane since you've already experienced flying in one before.