Look at the bottom end of the average salaries of the career you are interested in and ask yourself whether you'd be able to survive on that if you got one of those jobs.
Similarly, look around other, similar jobs, and make sure you're not looking at a job title that's middle-career when you should be looking at something more entry level.
If you're aiming at the same job as someone with years of experience in the field and more developed skills, you probably won't beat them out for the same gig. Aim strategically and choose opportunities that you know you can excel in.
When assessing your chances on a certain career path, the key question is:
With enough time, could you get good enough at this game to potentially reach whatever your definition of success is in that career?