If you could care less about your grammar mistakes... then you are already making one.
Because it should be "I couldn't care less."
And it's not "first come first serve"... its actually "First come, first served."
But irregardless... actually, regardless of that, we are all making lots of grammar mistakes. And there are A LOT more.
See a big list ---> ***CLICK HERE*** ***CLICK HERE*** ***CLICK HERE***