Marrying without parent’s approval

For reference, I am 31 years old living in USA. I met the person I love at work, who happens to be Bengali and older than me. My parents are totally against this but I cannot let this person go. She makes me happy, I am myself with her, and we truly love another. We have been together for 2 years, initially, my parents agreed to an engagement and we had it done 2 months ago but now they are giving me the pushback.

I am at a point now where I want to do the Nikah without their presence. Has anyone does this? How did it go afterwards?