Yes Home Depot does have self checkout in their stores.
The home depot also has other checkouts so you can go to a cashier and have them ring up your items for you if you prefer.
But you can use the self checkout and they'll be someone nearby to help you if you need assistance with the self checkout or if something requires you to be 18 or over to purchase.
If you need to be 18 or older to purchase something and the self checkout says you need to be 18 or older to purchase the item or items then it will alert someone standing nearby to help you.
They will then enter a password and see if you're of age to purchase the item.