Boy LMN- You have guts- that's for sure. I have wanted to contact my half sibs so badly since my b-mom has chosen not to tell them- after 5 plus years now. (They are all in their late thirties and mid forties as well).
I haven't done it- but I think about it a lot. I can't wait to see how this turns out for you. I really hope that you get a favorable response. All this stuff is SO nerve-wracking and just makes you sick at your stomach.
You have waited way long enough, and you deserve to know your siblings as well as they have a right to know you.
I think our b-moms don't give their kids nearly enough credit when they keep us secret like this. I feel they underestimate their own kids.
The annoying thing about all this is figuring out which one to contact- since we don't really know personalities and relationships and past history. We don't know which member would be most receptive. It's all a crap shoot.
I admire you for going forward though. Good for you.
I'll be waiting to hear how it goes. Best wishes.