Leave it up to a kid! :roll:
I just enlarged it on my printer.
I printed out the original size, trimmed down to the cutting lines, placed on the printer being careful to get it lined up to the edges of the printer, enlarged to 120% (guess if you can't enlarge on your printer,this won't work), and print. Came up a hair short on the cut line but that is no problem as long as you get the parts you need for sewing ok.