I'm not exactly sure what you mean, but perhaps this is along the lines of what you were thinking:

foreach (sort {-M $a <=> -M $b} <*>)
{
    # ...
}
[download]

This will, in theory anyway, sort based on last modification time. -M returns a floating point value that is "days since last modification", and can be something like 0.2551 depending on your file.

If, instead, you mean you want to get all files within a certain modification period, you might want to go about it this way:

$oldest = 5;  # Days
$newest = 1;

foreach (<*>)
{
      next unless (-M $_ < $oldest && -M $_ > $newest);

      # Do stuff
}
[download]

Of course, you could condense this into a list with grep, something like:

$oldest = 5;  # Days
$newest = 1;

foreach (grep {-M $_ < $oldest && -M $_ > $newest} <*>)
{
      # Do stuff
}
[download]

Typically, though, you would likely use readdir instead of a glob for this kind of read.