如何检查Magento中是否有类别？

In front-end I am displaying all category of first level.

Now I want to check Is there any category either available or not in first level.

I am using this code and getting all categories.

public function getCategory()
    {
        $parentCategoryId = Mage::app()->getStore()->getRootCategoryId();
        $categories = Mage::getModel('catalog/category')
            ->getCollection()
            ->addFieldToFilter('parent_id', array('eq'=>$parentCategoryId))
            ->addFieldToFilter('is_active', array('eq'=>'1'))
            ->addAttributeToFilter('level', 2)
            ->addAttributeToSelect('*');
        return $categories;
    }

If there is no category available then I want to display a message but I don't know how to check category is available or not in first level.

To check if the category exists at the first level

$categories = Mage::getModel('catalog/category')->getCollection()
    ->addAttributeToSelect('*')//or you can just add some attributes
    ->addAttributeToFilter('level', 2)//2 is actually the first level
    ->addAttributeToFilter('is_active', 1)//if you want only active categories
;

    if(isset($categories) && !empty($categories->getData())) {
        echo "Category found";
    } else {
        echo "Category not found";
    }