Your parents know you a lot better than you know yourself, because you have been the center of their lives for your entire life. They are far more experienced in dating and relationships than you are. You would be a fool not to listen to their advice, and listen when they warn you about somebody. Remember that your parents love you, and want what's best for you. When you find the right guy I'm sure they'll be very supportive.
5 months into a relationship, you have a bunch of hormones raging through your system. You're not in love, you're just infatuated. You're certainly not thinking clearly. Your parents, who aren't infatuated, and don't have a bunch of crazy hormones running through their heads, but do care about you very much and do have a lot of knowledge on the subject of what sort of relationships work and which sort don't, are offering you honest advice. Shouldn't you at least hear what they have to say and consider it?
I've known lots of men and women who had their parents disapprove of their relationships, and the one thing in common about all of them was their relationships were messed up and ended up causing a lot of problems. These same men and women now wish they had listened to their parents' advice.
On the flip side, I've known more than a few people who did take their parents' advice seriously when their parents disapproved, and learned later about things the person they were formerly dating that horrified them, and were so grateful to their parents for warning them something wasn't right. For example, I know a woman who was very much infatuated with a man, wanted to marry him, but her father told her in no uncertain terms that he was bad news, after she brought him home to meet her parents. She was upset, but she listened, and a few weeks later broke things off. A year later she found out he was a con man who already had two other wives in two other cities!