Speculation fuel indeed.
Kanako fell into one of Tewi's bastard traps, but loli-Kana is so incredibly soft-hearted that she forgives Tewi for it?

Ain't Tewi so damn old that she might be older than Kanako?

Eh, once you get into the realm of the gods, things get a bit blurry. When they start existing and when they are recorded can be very unclear.

At the very least you can say that Tewi is Kanako's senior, since the former is very familiar with Lord Ookuninushi who is the parent of Takeminakata, the deity Kanako is based off from.

Wait... Isn't Tewi essentially Kanako's step-mom in a way?