Dont listen to that person it is fine because god wants all his children to be treated the same so you are a good christian because you arent being prejudice but god does like it if you try to...
Not if you guys really love each other, and just respect each other and you should be ok. It is not allowed in some Christian churches, and it may make the parents very upset.
I guess, if you're willing to put religion aside. The fact is religion is not that important a question in finding a potential mate or lover. Most couples have wildly different views on many topics....