WordPress Shortcode to calculate age in years, months and days

I have two PHP codes to calculate age in years, months and days

code I:

<?php
$dob = new DateTime('1978-09-29');
$today = new DateTime;
$age = $today->diff($dob);
echo $age->format('%y year, %m months dan %d days');
?>

code II:

<?php $dob = new DateTime('1978-09-29');
    $today   = new DateTime('today');
    $year = $dob->diff($today)->y;
    $month = $dob->diff($today)->m;
    $day = $dob->diff($today)->d;
    echo "Age is"." ".$year. " year"." ",$month. " months"." ".$day. " days";
?>

Can anyone help me? how to make the php code into a shortcode for wordpress.