What's to early to book?

You are totally fine on booking everything as soon as you want. You have your venue locked down so that is great. My advice since you want to book things soon soon soon. Just make sure you do your research like hard research on these vendors so that you won't second guess them later. I had a couple of friends that regretted hiring their vendors only to find another vendor that they wish they had hired but didn't know about them before. I was in the same boat as you, my now husband thought I was too eager to book everything, but because he told me to wait a bit I was able to really do some research on the vendors and honestly I would I hire them all again. Good luck and Congratulations!!