Magento 2 getExtensionAttributes return null

I am writing an Observer to MagentoCustomerAccountIndex but the Objects from class MagentoCustomerModelCustomer return null when getExtensionAttributes is executed.

$customer = $customerFactory->create()->load($customerID); //$customerRepository->get($customerID);
$ext = $customer->getExtensionAttributes();
if($ext == null){
    throw new Exception(" var ext = null");
}

I used CustomerRepository and CustomerFactory to get $customer