Hello,
Please make sure you have created the attributes properly, Navigate to WooCommerce > Products > Attributes and add a new attribute called for example“Age”.
After creating the attribute, you’ll need to assign it to your products. Go to each product and assign the appropriate age range to the “Age” attribute field.
Then Navigate to Appearance > Widgets > Add the WoodMart WooCommerce layered nav widget in the shop page widget area and select the attribute.
If the issue remains, Try to regenerate “Regenerate the product attributes lookup table” in Woocommerce > Status > Tools: https://take.ms/LGpvf
If you have any questions feel free to contact us.
Best Regards.