Plugin: Display First name instead of Username after login

I have a login plugin that displays username once the user logs in but
I want to display their first name instead.

Here is the code snippet that is responsible for doing this:
echo '<div class="login">' . $before_widget . $before_title . "Welcome ".$user_identity . $after_title . '</div>';

I tried to add $user_info->first_name in place of $user_identity but nothing shows up after “Welcome”

Any ideas what I’m doing wrong?
Thanks in advance