Laravel-Excel 2, get the year and month from "date" in Carbon format

In Laravel-Excel 2, I'm reading a file like this:

The code to read it is this:

$my_file ='some/path/to/my_file.xls';
$data = Excel::selectSheetsByIndex(0)->load($my_file, function($reader) {})->get()->toArray();

This it the output for dd($data[0]);, considering that datais an array:

I need to get the year (2005) and month (11) from "date". "date" is inside "fecha" and it is in Carbon format. How can I get it? I've been having a lot of problems reading that array-object thing. I thought that $data[0]["fecha"]->date would do the trick but, instead of that it works with:

$data[0]["fecha"].["date"]

But I'm having some errors in some versions of php with "Array to string conversion", but in my php it doesn't show the error, so how should I get that year and month? I don't get it.

This is the output of print_r($data[0]);die();:

Array (
    [fecha] => Carbon\Carbon Object (
        [date] => 2005-11-01 00:00:00.000000 [timezone_type] => 3 [timezone] => America/Santiago 
    ) 
    [hora] => 
    [bloquefr] => N 
    [dia] => 1 
    [activo_defecto] => 118.209 
    [reactivo_defecto] => 0 
    [empresa] => Luz Osorno 
    [barra_internal_name] => La Union 13.8 
    [barra_cen_name] => La Union 13.8 
    [barra_cne_name] => L.UNION_______013 
    [barra_cen_name_2] => La Union 1 023 
    [tipo_barra] => SPD 
)

via Chebli Mohamed