AITA for telling my former teacher to mind her own womb

I (F40) had always planned to have at least 2 kids, but life didn't work out that way, so hubby (42M) and I super grateful for the one that we've been raising for 13 years. Close family know the circumstances but it's not something we share with everyone.
Trouble is, this one teacher I have from elementary school is always sending messages for me through my mom that she thinks we should "try for the girl". I've brushed it off for a while, and even told my mom to stop sharing the messages since she knows why we have only one. They stopped for a while and then last week, the teacher visited my mom and again sent a message. My mom laughed it off and when she related the exchange it was framed as "I don't know why she won't just drop this."
I asked for the phone number and called my former teacher. She was pleasantly suprised to hear my voice after all this time, but I got to the point and told her, "Respectfully, please stop sending these messages. Not everyone who has one kid had a choice and it's hurtful every time I get one your messages.". I stopped short of telling her to mind her own womb. She tried to brush it off as just banter, and her tone became defensive. In the end she said "Fine, I won't send any messages again." Then she hung up.
I tried, for my mom's sake, to be as polite as possible, but I'm wondering if I should have just kept ignoring her as I've been doing for years. In my culture we don't usually "talk back" to elders, but I'm just fed up of these kinds of comments and hers was the proverbial straw that broke the camel's back. I'm worried I might have cost my mom a longstanding friendship, but she supports the stand I took, so...did I overreact?