parents donot allow to marry saying age difference to little and not from the same sect

salam Alikum, I am 20 years, male, international student from pakistan. this last ra madan a Pakistani, sunni girl here got interested in me, and after getting to k now her I also got interested in her and we promised each other that we will on ly marry each other.We wanted to do everything islamically,however we did at a point forget the rules and did kiss each other. Both of us have been truly repe nting since then We were about to tell her parents but they found out before us and they say that we cannot marry for the following reasons: 1)I am urdu-speeking, she is punjabi. 2)I want to get green card thats why i want to marry her. 3)Age difference to little( she is 6 months younger to me). 4)Says we are immature. Her paretns told me not to meet or call her, and i havent done that since then, we want to do everything islamically. we love each other a lot. kindly tell what she should do to convince her parents. Her parents dont even want to meet me. and what should I be doign now. jazakumullah