Creating a startup because those you follow talk about it should be the first sign that you are leading yourself astray. It's easy to devote time to something others are doing.
Accepting uncertainty feels destabilizing. Trends take the ambiguity from what you're working toward. Desperation latches onto trends, and devoting time an effort into capitalizing on them can lull you into a seemingly certain future.
But once you jump on a trend, it becomes difficult to be critical of your early decisions because, in effect, you never made any decisions. The trend made them for you.
It's like catching a wave without a surfboard. You will get caught in forces much larger than yourself, while others with surfboards are riding the wave in ways that you just cannot. Learning to surf is difficult, and so many don't take the time needed to learn.
Instead of searching for your calling, discover your proclivities. Be comfortable learning about yourself without fear of exporting it into the world too early, or applying it to a hyped business venture. Grow your strengths so you know when and how to catch a trend.