Answer:
Yes. If you’re a Christian, dating a non-christian is just going to pull you away from God, whether that person means to or not. You become most like the people you spend time with. And in a relationship, you spend a lot of time with that person.
Here is some Scripture defending this answer:
“Do not be unequally yoked with unbelievers. For what partnership has righteousness with lawlessness? Or what fellowship has light with darkness?” 2 Cor. 6:14
“Do not be deceived: “Bad company ruins good morals.” 1 Cor. 15:33
“For where your treasure is, there your heart will be also.” - Matthew 6:21 (if you treasure a boyfriend/girlfriend who is a non-believer, you’re heart will be with theirs. And theirs would not be in the right place).
“I appeal to you therefore, brothers, by the mercies of God, to present your bodies as a living sacrifice, holy and acceptable to God, which is your spiritual worship. Do not be conformed to this world, but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect.” - Romans 12:1-2 (key sentence: Do not be conformed to this world).