Tisha, roses that are 14-16 years old certainly should be taller than 12 inches by now, unless they're roses that aren't appropriate for your zone and consequently die back each winter and struggle to come back each spring.
I think you should go ahead with your project. Make sure your containers have sufficient holes for drainage and get those roses into the containers before it gets too cold. I'll leave the winterizing advice to someone else because I've never gardened anywhere but zone 9.
