OP had two years of experience before joining the startup. I'll give them the benefit of the doubt of not knowing things like "doing the math". When you are a

OP had two years of experience before joining the startup. I'll give them the benefit of the doubt of not knowing things like "doing the math". When you are a relatively new grad working an entry level job at a big Co and what you hear are mostly stories of all your friends of friends who became millionaires being an early employee of Uber/Snap/Twitter/whatever, it's tempting to make the jump.