Welcome to BYC! I've had chickens all of my life and currently have over 40, so I know a thing or two about chickens! I also have ducks, dogs, cats, fish and bearded dragons.
Check local laws and ordinances to see if you can keep chickens, roosters and the number of chickens you can keep. Some places have a no rooster policy and some have a strict number of chickens you can keep, especially when living in a city. You can go to this fourm for some help in that.
https://www.backyardchickens.com/forums/local-chicken-laws-ordinances.37/
Build bigger than you think your going to need. More room is always better!
And you can get more chickens! Shh no need to tell your husband.
Think about what breeds you would you like. If you want a large egg production
and a long life span I wouldn't go for a production hen, like a ISA Brown as they usually have a shorter life span. Hens slowly stop laying the older they get with any breed. I have a large list of what breeds lay what color eggs here:
https://www.backyardchickens.com/threads/looking-for-layers-of-pink-eggs.1281832/#post-20680561
What are you going to do with the poop and bedding? Figure that out before you get them.
Are you going to have a run? Or free-range? Or a mix of both?
Do you have a garden? If you do, you won't when you let the chickens anywhere near it! Some chicken wire will help keeping them out. Remember if your using wire for your coop don't use chicken wire, use some type of welded wire. Chicken wire is for keeping chickens in (or out of a beautiful garden) not for keeping predators out.
See what type of coop you need. If you live in a warm place like Florida, where I live, a open air coop is a good option because of the hot and humid summers. Fans and frozen treats are also a life saver here.
If you live in a cold place a enclosed coop is better. Here are some coop ideas and a fourm for help.
https://www.backyardchickens.com/forums/coop-run-design-construction-maintenance.9/
https://www.backyardchickens.com/articles/category/chicken-coops.12/
Think about where you will be getting your chickens. Will you get chicks from a hatchery? Or a breeder? Would you rather get young adult females, pullets? Or chicks? Maybe adults? Do you want any males?
I hope your chicken adventure goes well!