I'm have an array of arrays in which I am trying to find the number of indices for any of the referenced arrays(they should all be the same).

Well, that's not what the title of your node asks for, but it is easy enough...

my @AoA = ( [1,3,5,7] );       
print scalar @{$AoA[0]};        # 4
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To get what the title asks for, the last element index, you can use...

 
print $#{$AoA[0]};              # 3
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-sauoq
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