Is offering free premium to initial users a good idea?

So i recently made my first app Spenlys.com a ai powered personal finance app. But as you know ai is pretty expensive and getting initial users also kinda hard. So I made this approach - I lock some features behind a paywall (fake) when the users clicks the upgrade to premium, They get pro for free as a way of thanking for trying the app early and then I ask the user - "You got the premium for free would you have paid for it? " So I know if users are willing to pay for the features (validation) . I don't have enough data currently so I can't share it. I just want feedback if it's a good validation approach if you have already built the feature. What do you think?