I can't remember precisely what your wording was, only the sentiment it expressed, and I believe that sentiment was along the lines of "she was born a man".

The trans experience (in fact, the experience of gender for any human being) is varied, personal and unique to each person, and as such there is nobody on this earth who can say what gender she was when she was younger is her.

Doctors and other medical professionals could have taken a look at what sex characteristics she exhibited at birth, and decided that mostly fits into the bucket of "male". For the majority of people gender and sex line up neatly, and as such the two are often conflated as being the same thing.

To assert that she was "born a man" you must make this incorrect assumption that gender and sex assignment are the same concepts - but this is false (and harmful to propagate)

She was assigned male at birth (presumably) and she may have experienced gender as a boy/man for quite some time growing up, or she may have always felt something wasn't quite righ, or she might have had some completely unique experience of gender that I could never even dream up as an example for you. The only person who can say if she was born a man is her. Doctors can say if she was born with male sex characteristics.

I know I'm repeating myself somewhat, but I hope this helps.

Edit: I knew I'd forget something as well.

Even if your sentiment had been "she was born a male" (which, god, you'd have to know her quite privately to be able to know that!), its not a particularly useful thing to bring to the conversation, and allusions to trans folks expressed sex characteristics that may not align with the gender they identify with is generally a bit of a dick move. Like a more intense version of telling a cis woman they have a manly face, I guess. And, a more appropriate way of expressing it if it is relevant to the conversation, is simply, "assigned male at birth".