And if it’s successful in 3.5 years I’d probably make a bit of money.Assuming this is about money rather than the fun and freedom you'll get at a startup, work out what you can do to improve the chances of success.
If your ideas are things like "write better code" or "increase test coverage" then you shouldn't join. Startups don't succeed because the code is higher quality (they sometimes fail because code is lower quality, but that's a different problem.)
If your ideas are around "promote the product by using my extensive list of contacts who would directly benefit from it" then join up, but realise your job won't be writing clever code, and the chance of that 5% being worth more than the difference in salary you'd make somewhere else are still very low.
