Can anyone(s) please tell me any downfalls of working under the table for an 18 year old. I'll be making 300-320 a week USD under the table (no tax).

Will they actually findout/ look into it, or ever notice only if I have the job for like a year or so ? Aside from not contributing to my 401k plan, what else is wrong about this ?

Should I sign one of those 1011 forms ? I really would rather evade taxes, as I feel like they are not properly utilized.