Yes, like you assumed, your dog is showing affection. Licking is a functional behavior that puppies learn from their mothers as a way of showing love. Maternal licking as well as licking between littermates is a way of strengthening familial bonds. So, your dog might be licking your face in order to form a closer bond between the two of you.
Also, I think there’s another reason why your dog licks your face all the time, she is grooming you! Naturally, dogs lick themselves and each other in order to clean. This act of grooming is also an intimate behavior. If your dog licks you frequently, they might be trying to clean and groom you. It could be gross for you, but it’s the way she loves you!