PHP - 帮我从数据库中的序列化值数组中获取值

This is my serialize values in my database when I tried fetching using PHP

$mylink = $wpdb->get_row( "SELECT * FROM wp_hlsq_signups WHERE user_email = 'john.r3@domain.com'" );
$metaData= $mylink->meta;
echo "<pre> $metaData</pre>";

This is the Output:

a:6:{
s:10:"first_name";s:4:"John";s:9:"last_name";s:6:"Ratina";s:9:"user_pass";s:34:"$P$B3EtpszNVkYJseassseaa2$swas";s:10:"user_email";s:14:"john.r3@domain.com";s:10:"user_login";s:6:"john-r";s:4:"role";s:10:"subscriber";
}

I just want to display John Ratina which is first_name and last_name in php, how it's possible?

$metaData= $mylink->meta;
$valData= unserialize($metaData);
echo $valData['first_name'];