Adding in after the fact...
I'm probably adding my 2cents after the fact! lol! However, I think you are making the right decision with the 10-speed, I run a 10speed durace, it's flat here in Florida for cross, and it worked well in Georgia for other types of hillier races. Also I road train a lot on my cross bike, it's easy to switch out my road wheels, (rather than having to wrestle with tires) and my husband has awesome wheels that are 10 speed so then I can switch out with him and use his wheels :p
You should try cross racing! Racing cyclocross is really fun, low key without a lot of pressure, unless you want to have pressure. Very different from the road scene.