Hello

and Welcome To BYC! Congratulations on your new home! Sounds like you are going to have a really busy spring and summer getting everything planted and done!
If you can manage the birds, I would consider getting both chicks and older birds. Like Wyandottes7 said, chicks are really cute and fun to have and they tend to grow into tamer chickens if you work with them from the beginning, and you can often find chicks of breeds you can't find as older birds, but they are a lot more work and are more delicate...
With older birds, they don't tend to be as tame since they usually have not been treated like pets, but on the other hand getting eggs four or five months sooner with older birds is really nice, if you work with them, especially bribing them with food, they usually do come around and and become friendly.
The big problem is you will not be able to combine the two ages until the babies are about the same size as the older birds... the best method is usually a few weeks or more of seeing but not touching each other through wire, so you would need to either have your coop divided into two sections or figure out some way to have a cage etc inside the coop for the babies while they get to know each other. The Learning Center has a good article on integrating flocks (after the quarantine section)
www.backyardchickens.com/web/viewblog.php?id=2593-adding-to-your-flock
You might also like to check out the BYC Learning Center, lots of good articles on all aspects of chicken keeping.
https://www.backyardchickens.com/atype/1/Learning_Center And it is always fun to check out your state thread for chicken keeping neighbors
https://www.backyardchickens.com/t/270925/find-your-states-thread