[ddavidn]

As others have said, the key points are that you should ask for at least a barebones salary and you will likely be replaced if this company takes off. However, this could be a great opportunity and you shouldn't let fear or self-doubt drive your decision.

One thing I'd like to add, assuming the financials work out and everyone is happy, is that moving from CS/programming to a CTO position is going to require quite a different skillset. You probably won't be programming all the time, at least not after whatever project they have in mind is in a stable place. You will potentially be responsible for reporting/BI/analytics, systems architecture and administration, tech support (Yes, everyone is going to ask you for help with their computers), and anything else tech-related that comes up along the way. If you want to stay in good shape as a programmer, you'll be responsible to find the focused time to code, keeping your skills sharp and current, and staying motivated to do so. At this time, you'd normally go work with an established development team who can guide and mentor you, as well as balance the team so that you have time and resources with which to further your skills.

The only thing in your post that makes me think this may be a good opportunity to explore is when you mention entrepreneurship as your long-term goal. This is likely going to be a great crash-course in how difficult that can be. My advice, though, would be to get great at what you know and learned, spend a couple years on a great dev team, save some money, and I bet there will still be opportunities for you to get into a startup for all or mostly equity.

Hope this helps. I'm just a young guy who's seen some different sides of the equation.

[Perados]

Great answer, thanks! I consider learning that new skillset as a pro, not a con, and I really enjoy team management.

Regarding your advice, that is exactly what my long-term plan was: getting a stable job for a few years, then become an entrepreneur. But that is everybody's plan, right? Everybody wants to eventually become his own boss, but the reality is that once people get a comfortable life, it is very unlikely that they will leave that comfort zone. I don't know if that would be my case, but I think it is definitely something to consider.

[ddavidn]

I think if you have the drive to become an entrepreneur, you will. My experience, really quickly, is: Intern programmer, two years college, two years working, one year entrepreneur, at my current job for three years. I spent one year doing freelance consulting and development, and it was a blast. I had fun, but didn't make quite enough money to live on, and found a job I was happy with. I freelance on the side now. But I'd do it full-time again in a heartbeat if I could save up some money and line up some steady monthly work. I don't think starting your own business is everyone's plan. From how you're presenting things, I personally think it's very likely that you will leave the "comfort zone" you mentioned. My reasoning: It won't be your comfort zone. I've never felt comfortable just doing a 40-hour week, and I think that underlying entrepreneurial spirit keeps me from being comfortable with the mediocre and ordinary (which my job isn't).

I also hang out with a couple people that bootstrapped their own product/service while working a full-time development job and they now run successful businesses by themselves, after running it "on the side" for 1-2 years.