Well, on the one hand, you are at a unique the time of your life when you can invest your time into a startup (assuming you are single, and willing to eat some ramen). On the other hand, clearly you could be doing better, and any skills/experience/salary history you acquire now will put you in a very attractive position in a few years, and really will compound for the rest of your life.

I think you need to do some soul searching, and ask what is your motivation, what is your passion? Are you in this startup because you believe in it, think it can fly, and are willing to sacrifice a lot? Or are you there because you fell into it, they gave you a job, they're good guys, etc?

Other questions to ask are:

- What's your risk tolerance?

- Do you mean to have a family some day?

- How important is money to your situation?

- What would you value more: the experience of building something yourself, or the experience of working on a team?