To become great at something, you have to put in the time and really obsess over it.
But now, there are so many 'somethings' to choose from and each choice feels like a binding investment. It is hard to choose the 'something' you want to do because, well, what if it doesn't work out? Sure, you could spend all your time on one thing but what if it doesn't pan out, not only in the broad sense of success but also in terms of providing money to support yourself?
Granted, this is definitely the result-oriented rather than process-oriented view. Ideally we would do things because we want to do them, not because we want what we could get as a result of doing them. That is hard to put into practice. I'm sure people have grappled with this for ages but it feels particularly difficult now with so many options and so many people trying to give you advice and telling you 'you can do anything.'
Now, this is an extremely privileged position to be in and I think that demands that some risks be taken. Gamble on yourself, go for it, and if something doesn't work out, fix it or move on. Better to live in constant risk than in 'quiet desperation.'