Just to clarify, my recommendation not to book now was specific to your question regarding AS. Typically speaking, you are not going to get AS' best price this far out. Yes, you could change the ticket under the current policy, but you will not get a refund, only a credit. That may or may not matter to you.
Several people have chimed in about how you should book now and have referenced that they have done so with other carriers. I don't see the relevance of that to your question.