@age = ( @f1 = (amy,35), @f2=(bill,55), @f3=(george,28), @f4=(jason,71
+));
@age = sort personal::sortAge(\@age);
[download]

this is not what you want¹ ... anonymous arrays are written in brackets.

you rather meant:

  DB<150> @age
 => (["amy", 35], ["bill", 55], ["george", 28], ["jason", 71])

  DB<151> sort personel::sortAge @age
 => (["jason", 71], ["bill", 55], ["amy", 35], ["george", 28])
[download]

your syntax produced a flat list, not a nested AoA.

  DB<153> @age = ( @f1 = (amy,35), @f2=(bill,55), @f3=(george,28), @f4
+=(jason,71));
 => ("amy", 35, "bill", 55, "george", 28, "jason", 71)
[download]

see perldsc for details.

If I were you I would define sortAge() to sort itself

  DB<157> @age = ( ["amy", 35], ["bill", 55], ["george", 28], ["jason"
+,71]);
 => (["amy", 35], ["bill", 55], ["george", 28], ["jason", 71])

  DB<158> sub personel::sortAge { sort { $b->[1] <=> $a->[1] } @_}

  DB<159> personel::sortAge @age
 => (["jason", 71], ["bill", 55], ["amy", 35], ["george", 28])
[download]

otherwise better rename your sortAge to cmpAge, cause your code doesn't "sort" it "compares".

¹) and the code you posted before updating wasn't even valid perl.