which Platform & Niche Is better and how do i find if a niche is good or not? Newbie Tryna Get First Digital Product And Make Money

Im a College Student RIght Now Got Keep Interest In digital Product And Selling and solving the problem for people which Platform Should I Choose For

im Tryna Sell To Genz And Millenials im Good With Finance and budgeting and Getting Out Of Debts

I Have a good Physique Too i can Teach About that Too

Any Amount of Help is Great

Thank you People