@Aisha176 if I understand you rightly, you are saying that whether we define 'woman' by gender identity or by biological sex is a matter of personal preference?
Choosing biological sex to define women rather than gender identity is not just personal preference, it has solid advantages:
Biological sex is universal. All humans (including those with differences in sex development) have a biological sex
Biological sex is constant. Humans' biological sex remains the same throughout their lifetime. No human has ever changed from producing eggs to producing sperm (or vice versa)
Biological sex can be objectively measured. It can be deduced from appearance alone with near 100% accuracy by most casual onlookers. A scientist or doctor in possession of the full facts will be able to determine it with 100% accuracy
Gender identity has none of these advantages:
Gender identity is not universal. Many people (including me) don't have a gender identity
Gender identity is not constant. As evidenced by gender fluid people and detransitioners
Gender identity cannot be objectively measured. Because is supposedly someone's internal sense of their gender, it can't be determined by objective bystanders
Scientists use biological sex to define women and men. So do the vast majority of ordinary people. And the UK Supreme Court ruled in 2025 that it is the legal definition.
Biological sex evolved 1.2 billion years ago. Denying its reality is akin to being a flat earther. You can argue it is subjective all you like, but when humanity ceased to exist the world will keep spinning and animals will keep shagging