I also have not had a problem resizing partitions using gparted
or doing it in Ubuntu during the Live CD/DVD install.

That said, it is prudent to save all your data, especially the most important
data you don't want to loose.

You could do that by saving to a CD or multiple CDs or DVDs. If that isn't big
enough may be a 32GB flashdrive.

I have a older 68GB IDE drive that I backup my entire Ubuntu /home partition now
and then. The last backup, actually a copy to, takes up over 14GB.

You can have multiple copies or revs of Ubuntu on that HD and all can use the
same /home partition. Whatever is in that partition that you have access to, you
can have access to in any of the revs of Ubuntu because they all are looking at
the same data.