As Salina Mendoza has answered, you need to find your passion, and then see if that passion includes devoting your life to imagining, creating and running a business. Being an entrepreneur isn't a career that one sets out to pursue, like being a lawyer or accountant or architect. Rather, it is something innate, that results in a compulsive passion to start a business.

The best entrepreneurs then learn to harness that energy and passion, and apply it to all the technical steps that are necessary to found a successful startup.

I'm going to suggest three books for you to read to understand what this Entrepreneurship stuff is all about. None are very long or complicated, and I'd suggest reading them in this sequence:

This classic book will help you understand the difference between working in a startup, and actually founding one as an entrepreneur.

2. Lucky Or Smart?: Fifty Pages for the First-Time Entrepreneur, by Bo Peabody

This short, quick-to-read book by one of the very early Internet pioneers in the dotcom boom will give you a great personal view from someone in your shoes (and possibly your age) who found himself almost accidentally a big-time entrepreneur. It's definitely worth the read.

Finally, although it's a bit of conflict of interest, I strongly suggest you read:

3. The Startup Checklist: 25 Steps to a Scalable, High-Growth Business by David S. Rose

Yup, it's by me, so take the recommendation with a grain of salt. That said, I wrote the book to be the step-by-step guide for entrepreneurs to founding a real startup. If Gerber is the “why”, and Peabody is the “what”, my book is very much the “how”. It requires no prior knowledge about entrepreneurship, and walks you through the specific things that are involved in founding a startup. Once you decided to take the plunge, it should be your always-at-hand checklist of what to do next, and how to do it.

Good luck as you consider your future!