I wouldn’t tell before going into the 2nd Trimester. That is my personal feeling about this. others may feel differently. I would tell parents/grandparents first, then my sibs, followed by other relatives, and friends. I would probably wait until I was showing before telling most people, other than my most imemdiate family.
I had a friend who didn’t tell me until she was ready to give birth. That is extreme. I also had the experience, sadly, of telling my in-laws I was expecting my second child, only to literally begin miscarrying seconds later. Had I waited even one minute more to tell them the news (it was Chanukah, and we went over to see them, and I told them I had a special Chanukah present for them), I would never have said a word about it and they would not have had to deal with the sad news that we lost the baby.
B’shaa tova umutzlachas by you. You should have a beautiful, healthy pregnancy and very easy delivery of a healthy, wonderful baby, BE”H. I personalyl would want to know the gender of the baby, especially if a Sholom Zochor and Bris might be in the works. But I would only tell people on a need to know basis. Grandparents probably fit into that category.