I got a new boxer puppy last weekend. The pool is supposed to be completed by the end of the week. So at what age is appropriate to introduce the new dog to the pool?

Chloe is only 12 weeks right now. The pool has a ledge about 4' wide and will be about 6" of water, but if she walks off she will be in 3 1/2' of water - can all dogs swim from birth?