Cold feet about attending PhD program
I was in industry before returning for a PhD (in neuroscience). I don't know that I regret it, but I do often wonder what my life would have been like if I stayed in industry. For me, one determining factor in returning to school was that I didn't enjoy working on other people's questions. As a software developer, I was always solving the client's problems. As a scientist, I was working on things that interested me (and my advisors).

Factors you might want to consider:


If you decide not to attend, how upset will your future advisor and school be? Will you be burning bridges?
Could you work for a few more years (maybe saving some money) and then decide to get a PhD?
The salary for a CS PhD is generally not that bad. It is not the same as being a penniless undergrad.


I think you should talk to your advisor and let them know how your are feeling. That will give them a chance to provide advice, and also gives them a heads up that you are having 2nd thoughts (which seem totally reasonable to me). If they react badly (which they might do), that is a sign that this relationship might run into trouble anyway over the course of the degree.