I understand how you feel. Actually, I am getting my first mammogram on Thu, since I am 40 and when I got an IUD some weeks ago, my dr suggested we do it when I come for that follow up appt. I am not worried about it, but I also haven't mentioned it to my mom; just my boyfriend since he's fully in the loop on my GYN visit for birth control.
And that is because....the lesson has been hammered into my head- I hope I am finally getting it!- that at some point my mom shares things I wish she wouldn't. Like telling my dad about my IUD- the phone call from him, expressing his huge concern over me getting pregnant in my first year of sobriety (or ever) was embarrassing to say the least. Part of my mom's issue is her worry- she catastrophizes everything, ie my current bout of strep means I won't be able to go to DC in two weeks and I will lose the plane money and what if I make my bf sick and..... Part of it is her guilt as an alcoholic, part of it is her inability to be appropriate or discreet. Part of it is whatever. As I am regaining my independence and getting back to a place where PROPER boundaries can be in place- we were completely enmeshed at most points during my darkness, those last few years, in all ways- I have to learn NOT to go to her/them with "things."
Hard lesson. I know they care. I know that I get upset when things are shared that I want to control the message of when/where/why/etc.
Two takeaways from your post: no one can "jinx" what your results will be (I have this thinking too so I am also trying to remind myself of that!) and this is a one step at a time situation. Go to the dr. Get the results. Handle accordingly. And it sounds like we both need to be judicious about what we share.
Not a fun "lesson" with your family, but now you have info for future reference.
Hang in there.