Session variables NOT WAPPLER

I have an old website, that is not on Wappler yet, sadly. i need to make a few changes and need to use a session variable to pass information from page to page, and for the life of me i can not get it to work, but it should.

Page A

<?php 
	session_start();
	$_SESSION["themeSwitching"]="IOC";
	echo $_SESSION["themeSwitching"];
?>

Page B

<?php 
	session_start();
	echo $_SESSION["themeSwitching"];
?>

When i switch between PageA to PageB i would expect it to still echo IOC on PageB, but it just shows nothing. I am super confused.

I know it is not a Wappler question, but honestly 3 days later, I am just trying anything now.