I understand where you are coming from. I, too, have had second thoughts before TTC a third live baby. Unfortunately my last two pregnancies ended at 7/8 weeks before it was discovered I had a bad uterine infection that needed taking care of before getting pregnant again and so I still have yet to get my third child.
I did announce my last pregnancy to friends and family, only to be bashed for having another baby when we already had one of each. I was not deciding to get pregnant because I was ungrateful of what I had or that I wanted to replace the two we already have. It is simply because my husband and I always wanted a big family. I wasn't doing it out of spite or to be selfish. After I lost the baby that I had announced was on the way, telling everyone what had happened.
Well then my cousin, whom I'm close to, ended up having to get a hysterectomy after developing uterine cancer. I am thankful the cancer didn't spread but at the same time, I know how bad she wanted children and had the privilege taken away from her in the blink of an eye. She was also due to get married soon. It was horribly sad. I feel like me getting pregnant again may spite her after all she's been through and when I tell her this she said it is my life. She said: "If you want 10 kids you have my full support. We need some more kids in the family."
In truth, it is your choice. Nobody else's. I would say if you feel it is the best time, it doesn't matter what the others think. If they are true friends, they will cherish this time with you and understand that you are going through one of the best times of your life. If now is the best time to extend your family, I wouldn't wait.
I wish you the best of luck in whatever decision you choose