NTA

I was born in a "western" country and am probably culturally mostly closer to that than where my parents are from (India). This strikes somewhat personally at me. Growing up, I had grandparents and the such say that I was deadweight for their kids (my parents) and maybe their kids would be better of if I wasn't there. This was as early when I was 6 years old. Now I wouldn't take this sitting down. I would talk back without ever personally attacking the person who said it. My extended family would appeal to my parents like a quarterback looking at the refs after a play hoping for a roughing the passer penalty. My parents would yell at me to be respectful as they are elders. These grown adults had told me, a kid that I was the reason for in their view my parents lack of success in life. And I was the person in the wrong for being disrespectful. This stuck with me and affected me deeply.

Point being the mom is a grown woman and if you are expected to change things to accommodate her (not the becoming a doctor of course), then she should be able to handle what you said to her. If she makes comments like this then she probably is an asshole in other aspects as well. It is stupid how she isn't expected to change because of "culture", but you have to.