Hey Ruben welcome to BYC.
Chickens are addictive, I started with only five and small coop. Somehow my flock has grown to over 50 not including the turkeys.
Having said that, if six is the maximum number of chickens you plan to keep, that coop should work as it gives you roughly 5 feet per chicken. Have you thought about how are you going to clean the poop from inside? Are you having a swinging door so you can reach and clean the floor? or are you putting 1/2" hardware cloth as the floor so the poop drops down to the ground? I would attach the nest boxes on the outside so it would be easy to retrieve the eggs once they start laying. Check out the learning section here so you get some ideas about the watering and feeding the chickens. Good luck with your project.