Enamel pots are not optimal for brewing due to this very issue. As long as the enamel is not currently coming off, you should be safe to brew, but I would recommend going and at least picking up an aluminum stock pot. These can be found at the local restaurant supply stores and even Walmart. If you really want a good kettle, look for stainless, but aluminum will do just fine.
"Brewers enjoy working to make beer as much as drinking beer instead of working."