AITA for telling my co-worker her kids are none of my business?

School holidays are coming up and I have a co-worker panicking, as she left it too late to book vacation slots. My company had a rule where no more than 3 workers can leave at the same time for vacation. I already filled in my vacation slot months ago as I haven’t taken any in nearly a year.

I’m single and unmarried and in my 30s. Company HR told my co-worker that her only way to get her vacation is to get one of us who already had our vacation time approved to ‘trade with her’. And considering out of the three of us whose vacations were approved, I am the only female, guess who my co-worker approached for the trade?

She tried explaining (gently at first) that her kids (6 and 4 years of age apparently) were really looking forward to going to Disneyland and that everything is already booked, and if I can give up my vacation spot to her. I told her no, as I too already had my vacation booked (it’s a solo vacation but I’m not about to tell her that). She got real pushy and kept on trying to insist I give her my vacation spot, saying that “My kids would be so disappointed”.

I blew up at her after the fourth or fifth time, telling her that her “kids being disappointed” is none of my business. I didn’t exactly keep my voice down so at least half the office heard, and my co-worker turned red and left. One of my co-workers (25M) who sat to my side who had heard the entire conversation later told me that while he get where I’m coming from, I could be a lot gentler, and “I didn’t get how hard mothers get it”. AITA?