Reveal pregnancy on mom's birthday?

I'm torn on which way to go here- husband and I are tentatively planning on visiting my mom and stepdad on Dec 22nd for a little christmas get together, and that day is also my mom's 60th birthday! We are revealing the pregnancy to all our family members around Christmas, and that is the only day that husband and I have available to meet up with my mom (she lives a few hours away). And i also really want to tell her in person! She really want grandkids and this is my first pregnancy. Husband is worried that telling her on her birthday would take away from her special occasion, but I think she would be excited about it. What are your guys' thoughts?