Want to try for a 2nd baby but sister in-law is struggling with infertility

My husbands brother and his wife are exactly 10 years old than us. We are 24 and 28 and they are 34 and 38.

They have been together for a long time but put off having kids because they wanted to get ahead in their careers and buy a house...

In April of 2017 I found out I was pregnant (Unexpected but very welcome!)

My brother and sister in law, though loving were pretty critical of it since we were still in college.

Later my sister in law told me that they had been trying for a baby for a few months. I was excited at the possibility of her being pregnant with me. But the months went by and my baby was born and she still wasn’t pregnant.

The birth of our baby brought a lot of questions from other family members to them about when will they have one. They kept responding that they are trying.

I felt bad for them but hoped that it would happen for them too. Well it’s been almost a year since my baby was born and she recently told me that they are still trying. It’s been almost two years.

We don’t have a really close relationship since we live far apart but we have a good relationship. She’s never talked to me about struggling with infertility but I know that she is.

Now that my son is about one, I want to try for another baby but I just feel so guilty about having two babies before she can have one. Even her best friend and her sister are pregnant right now.

Im going to be spending some time with her over Christmas and was wondering if I should talk to her about my plans to have another baby? Or just let her know when it happens... I don’t want her to be blindsided and I want to be sensitive. Am I overthinking this?

Thanks for reading my book! 😂