As of now only our best friends know we're pregnant, and I'm kind of stuck on what to do about our parents.

The scenario -
My DH's parents live really far away and will be visiting when I'm almost 6 weeks pregnant, and we have a dinner planned with his parents and my parents. Perfect opportunity right?

Not to mention, my mom who has been asking for grand babies since I was basically a teenager will lose her s**t when she finds out... so I'm super excited to tell her. AND it's her birthday that week - so it's the perfect scenario to give her a gift in front of everyone that announces.

My issues -
1) It's so early and that's a bit nerve-racking my first appointment isn't until I'm 8 weeks.
2) My mom sucks at keeping secrets. Before my DH proposed he asked her not to tell anyone, and I don't think she kept her mouth shut to anyone she saw before it happened. And this is super concerning for me.

I don't know if I can share with her the importance that this is our news to share, it's fragile news, and she doesn't have the right to share it until we're ready. I mean, she is an adult and I want to believe she'll keep quiet, but she just has trouble keeping secrets when she's excited about something.

Would you take advantage of the golden opportunity (since I have no idea when DH's parents will be visiting again), or wait a bit longer to share? I am worried she would figure it out before and I would lose the chance to surprise her.