Thanks for asking your question. Parents always want the best for their children and their meddling in their children’s love life is the stuff of classic literature (Romeo and Juliet) and classic research and advice columns.
The long and short of it is that they have given you their input, and that is the end of it. What they don’t know is that there is often a boomerang effect: The more they push you to leave the least likely it is you wouldn’t separate even if it were in your best interest.
Explain to them that you know they love you and they are acting in a way they think is helpful, but it isn’t. You understand how they feel, but at 20 you want to make your own decisions, good or not, and that them repeating what they have already said is actually pushing you away.
Finally, stop having the conversation. When it comes up explain that it doesn’t make you feel good to keep justifying your life to them. Ultimately keep making plans for your financial and emotional independence. It is time.