Would you stop TTC if your kids start TTC?

So I’m 20 years old and recently married. My husband and I are TTC baby #1. My father is married to a woman who is 27 years old and wants to have a baby. My dad does not want to have kids with her (he has expressed this to me). She has been very persistent. So she told me back in June that she gets jealous when other women get pregnant because she’s been trying for a baby. I’m worried. My dad is just ready to start saving his extra money for a retirement fund (he had 4 kids and no extra money for the last 22 years) and start enjoying his empty nest. She does not want to back off. She’s on and off about the idea of TTC. Like she gets baby fever and wants to have a baby, and then two months later decides that she doesn’t like having responsibilities and she just wants to party. This is exactly the reason my dad doesn’t want to have kids with her. And now that I’m TTC, I feel like she’s going out of her way to rub it in my face that she’s older/wiser and in a better place than me financially. Oh and I forgot to mention, she recently had surgery for cervical cancer, and they had to shave off so much of her cervix that they advised her to not have children because it can cause severe complications. It feels like she’s trying to race me and put me down for TTC. If you had kids who were TTC, would you stop TTC and just wait for your grandchildren to arrive?