"we kids" is correct and usable in written English.
You can use it to refer to a group of children, typically including the speaker. For example: "We kids had a great time at the amusement park yesterday."
We kids were oblivious to the big picture.
Cosell was always nervous that we kids wouldn't show up on time.
We kids were all on our own on the streets starting in kindergarten.
My mom danced with my dad, and we kids paired off with each other.
We kids were like little rats down there, hungry, jumping on all that stuff.
We kids waved back, we cheered; we were bit players in a timeless scenario.
My father got his gin; we kids got nothing but scratches and twiggy hair.
My sisters and I didn't know it then, but we kids had it easy.
But we kids preferred English Christmas cake with white icing that cracked your teeth.
Dad used to describe his great nights out (before we kids came along).
And we kids watchhim draw the head of the fierce snake, its black body striped yellow.
