So far as I know, there isn't, sorry. The only way I am aware of is to
boot with a live CD; use gparted to shrink the existing partition and
create a new one in the freed space; edit /etc/fstab to add the newly
created partition and tell the system to mount it at /home; copy your
files into the newly created /home partition.

It really isn't hard, honest. So long as you don't change anything
already in fstab and only add your new /home (or, possibly, simply
change the old /home entry, if it exists, to point to the new partition)
then you can't do too much to damage the system.

There is a very slight risk that the gparted operations might possibly
damage the filesystem, but all I can say is that, in five years of using
gparted to do some pretty weird things to my filesystems, I have never
had a problem.

Oh, and no, you are most definitely not crazy to be attempting this.
There are all sorts of good reasons for having /home on a separate
partition, not least of which is the fact that you'll learn something
new