Originally Posted by
EuroTrashDude
Both of your bikes look like pretty mild recreational bikes. What type of riding do you do now? Do you ride off-road? Single-track? Group rides?
CX racing at any level requires very well-developed bike-handling skills as well as a high-level of fitness. People don't want to race along side anyone who lacks handling skills & group riding skills. Crashing sucks. Medical bills suck.
If you are not already, consider doing some group road riding and off-road riding. Check your local bike club -or- meetup.com for group rides near you. Start training now. After you start training, you'll want (and deserve) a better bike.
Gosh are you serious. It's cyclocross, for crying out loud. The OP isn't going to be racing alongside anyone for more than a minute or so, and he'll be mixed in with all the other n00bs in Cat 5. There is not exactly a lot handling skill to go around in that group to begin with. Group rides are a perfectly good idea, but consider removing that stick. Cross is about the best possible, least dangerous place for a brand-new racer to start. Only way to develop those handling skills is to get practice driving a bike at race pace, in the red.
To duketg: I would suggest you'd be better off starting with your MTB, but you'd be better off still with even an extry-level cyclocross bike. Neither of your current bikes is really going to ride or handle anything like a cross bike.