The whole thing depend on you. What do you want? What are your expectations ? Business has many ups and downs and things are uncertain. It's a probability. Things might or might not work out. You might or might not make money. You might or might not be famous. So if you are okay with these uncertainties and ready to accept your fate, definitely go for your startup plan. Now, on the other hand, if you are not sure and not ready to accept the downs and want a constant financial support or you have a family to look after to and ready for the regular grind and a boss always hovering, then go for the job. Both of them have their own pros and cons. You need to decide what you want. You get freedom on own hand and obeying orders on other. You have steady flow of income and on the other hand, a constant worry of money. Think and decide wisely. 

Know the differences between the two - then know what you really want and are wired to do.

JOB:

• Someone else telling you what to do and how to do it.
• Set hours
• Often in the same location every day
• Limited opportunity in most cases
• Financial income is more regular
• Benefits often come with jobs
• You are trading time for money

YOUR OWN BUSINESS:

• YOU make the decision about all the things above
• The money may not be as consistent and secure at first
• You may go without benefits at first
• You'll initially be trading time for money but have the opportunity to change that over time.
• You get to be a lot more creative in what you do and produce.

I'm happy to clarify on any of these points. :)