File State tax forms too? At 71 I make less than req to file Fed but will do the Fed, because I raise my granddaughter, n want to avail the extra $500 stimulus?

Also...IF I had or decided to note any wage type cash earnings in last year, would that be a good idea, as I could then perhaps avail of the income earned tax credit? Based on any required  taxes on such, would it be worth it?