Should I Date my best friend of four years?

My best friend and I have been super good friends for years.4ish years ago we both had a crush on eachother that didn't get acted on. We both have Been in relationships since then but this is the first time we are both single at once. A few weekends ago we hungout for hours without anyone else because they were all busy. Something in me says I should go for t but I don't want to lose my best friend and everyone always said we act like an old marries couple or that we are dating.we big always said Ewwww since 4rs ago but now I'm unsure. Help!