I will give you my honest brotherly advice about this:
1- Talk to your parents about the actual idea of getting married. If you found that they are completely against it now and you don’t have any effective ways or convincing them (directly or through family members or friends), then you would have to postpone plans to get married for now. You have to be patient.
2- If they refused completely, the wisest thing to do is to stop communicating with the boy for now. If it’s going to be several years before your family would accept, staying in touch with the boy will:
-increase your emotional attachment to him, and this will in the long term affect your emotional and mental health
-lead to haram
And you honestly don’t want any such consequences.
Be honest with him. Tell him that you do want to marry him, but at this point your family won’t allow it. So it’s best not to communicate until it becomes realistic to get married then you can start talking to him again if you both would be still interested in doing so.
I understand this recommendation is not easy and not welcomed by your heart, but it is the rational way to proceed. Staying in touch with him regularly when you are not too close to marriage had many detrimental effects, and I see it all the time happening to our youth in our community. The best thing you can do to yourself and to him is to put everything on hold until you feel your family will approve. So I am not telling you to just end it for good. I am suggesting you tell him to put everything on hold for now. Don’t let him pressure you into staying in touch with him. Believe it will end up taking a huge emotional toll on you in the future. When you stay in touch with someone and you can’t marry them in the near future or can’t fulfill and of your emotional/physical desires with them, you end up getting frustrated and it will affect you negatively. So it’s best that you not put yourself in such a situation.
May Allah bless you and grant you the best outcome.