I'm just a rookie here, but don't you want a "-f" after the rm, so that it won't try to prompt you for each deletion?
As a side note, why not do this as a crontab entry, rather than a script? I run a crontab entry on my machines that runs every night at midnight and deletes any tiff files in a certain directory that are more than one day old. It looks like this:
0 0 * * * find /var/spool/drop_box/images -name "*TIF" -mtime +1 -exec rm -f {} \;
It could certainly be modified to suit your needs.
Allen