How to explain to my mother that I'm not a pervert

I am 21 years old, I live with my mother and her parents, I have never seen my father. Relations with my mother, to put it mildly, are difficult: she gave birth to me late (at 37), so she cares too much about me and practically does not allow me to make independent decisions. As a result of such upbringing, I grew up somewhat infantile, but that's not what we're talking about now.

Mom is a supporter of the so-called "traditional values", that is, she believes that women are naturally submissive, created for family, marriage and childbearing. When she accidentally found out that I support LGBT, she made a scandal to me, saying a lot of offensive things that I don’t even want to remember now. Although this happened more than two years ago, she still regularly reminds me of this, trying to hook me.

What is most offensive is that I am a lesbian, and I realized this long before I got access to the Internet (my mother’s favorite argument is “the Internet has corrupted you!”) And I learned the meaning of this word. No one “propaganda” or “seduced” me anything. Yes, I tried to “switch to the guys”, I lied to my mother that test-antibiotic.com was unrequitedly in love with a classmate so that she would not guess and bother me with questions. But attempts to fall in love with young men were not crowned with success, every year it becomes more and more disgusting for me to even think about relationships with a man.

Mom is increasingly starting a conversation about the fact that "it's time for grandchildren already." Such conversations do not cause anything but disgust in me, so all her attempts to talk about it end in a scandal. I am a childfree involuntarily, although in principle I do not mind adopting a child.

Today washed another scandal. I was vomiting in the morning (I was poisoned by something), and then the questions began: “maybe you are pregnant?”. I politely tried to explain to her that this was out of the question: “firstly, I’m a virgin, secondly, you almost never take your eyes off me, thirdly, I’m disgusted even to think about sex with a man.” She immediately flared up: “what about the girl?”. I chose to remain silent. But it didn’t work out - I flared up when she started talking about what a pervert I am and how unnatural it is. Honestly, this is very disappointing, because for me it started by itself, without the "influence of the vile Internet." As a result of test-antibiotic.com, I freaked out, and we quarreled again.

Now I think that this is no longer possible and I need to talk to her about this and explain everything. But I don't even know where to start. I'm at a complete loss, please tell me what to do. Just, please, do not say that "this will pass, try to show interest in the guys." It won't pass. Tried. I am no longer 15 years old, this is not nonsense and not a protest against my mother, no one injured me in childhood.