You have to decide whether you want an 11" or 13" model, it's that simple and only you can answer this. I had a 2011 13" MBA and upgraded to an 11" MBA in 2013. Best move I ever made, I like the 11" model much more. Something is just so cool about having all this power (I have the i7/8gb/512gb model) in such a small package with a decent variety of ports to connect things.
But you might hate the 11" model. There are endless threads on "which is better" here, just do a little searching. All comes down to personal preference. Now the 8gb RAM on the 13" model is better, but what's the point if you don't like the bigger computer?
Agree completely with this post.
I have had both the 13" and 11" MBA; both were CTO with the specifications of the model described by
@Boyd01 - namely, i7/8GB/512 GB SSD - and they each have been the best computer I have ever had.
In common with
@Boyd01, I now use the 11" as my sole computer - I travel a lot and the size of the 11" is wonderfully perfect for a portable lifestyle.
Now, to the OP: You must weight up the advantages of each computer and ask yourself what it is you need most from a computer. You must ask yourself what features you need, as opposed to those you merely want.
The 13" has a larger screen, and is a more powerful computer (that 8GB RAM); on the other hand, it has no warranty.
The 11" is a less powerful computer but - you say - does have a one year Apple warranty. If it has a one year Apple warranty, it should also be possible to buy Apple Care - which would extend the warranty for a further two years - giving a total of three years - for it.
Personally, while I like a powerful computer, I like a portable computer even more. Above all, I am fan of warranties, as that gives me peace of mind if something goes wrong.