Pinky, I thought, when I was writing this, it was possible some people would admit to having done something similar when they were surprised or something - I suppose in other words, I wanted to give my friend the benefit of the doubt.
I actually am happy to answer any questions but there's a way of asking those questions - one way is friendly and interested and another way is nosy and judgemental and your questions fall into the latter.
However, since your comment "test tube baby" makes me think you are genuinely very out of touch, I'll give you the benefit of the doubt.
It is possible to have a baby as a single woman, which indeed I am. This does not involve test tubes - IVF is one of the options but quite an invasive one; it's also very expensive. IUI using donor sperm is the method I will most probably be using. This involves placing semen inside the uterus.
Before even making an appointment at the fertility clinic, I had worked out costs of childcare: whilst I am not going to pretend I have every box ticked, I don't think anybody does (and - politely - I am not posting for advice about whether or not I should do it.)
I know this lady from my first job, as I have said, which was over ten years ago and we are also friends with another lady who also started with us. We are different ages and I am the youngest by quite a way. Perhaps on some level she still sees me as 22/23 (ah, if only!) and perhaps she thought that I was one of those people who would just never have children so it came as a surprise.