I do this especially with smallish quilts that I make for project Linus.
They are usually 50ish by 60 ish
I sandwich and pin, then trim the batting about a half inch larger than the top, and the backing a two or three inches larger than the batting. Then I turn the back under twice and pin to the front, probably just like you did!.
Then I can sew down the "binding" before I actually tie the quilt.