Your parents are adamant: 🛑 romantic relationships are out of the question for now. If you don’t agree with that, then you need to start a dialogue with them.
Choose a time that’s calm and suitable for discussion, for example around the table at the end of a meal. Tell your parents how you feel about their decision. Explain the reasons why you’d like to have a boyfriend or girlfriend: you feel ready, you want to experience an important relationship, etc. And let them express their fears: your parents surely aren’t trying to make you unhappy! On the contrary, they probably want to protect you.
Go gradually. Your parents may need time to get used to the idea that you’re ready for this experience. The passage of time will also relieve a lot of the tension. In short, you all need to clarify your perceptions and keep the lines of communication open.