Am I being to sensitive about this?

Back story, over the weekend I met my boyfriends ex wife and then we also got to meet her boyfriend, so it was a very overwhelming/overstimulating event for both of us. Things went fine as I’m not one to start anything in front of the kids because they don’t need to see any of us being argumentative about the things that they don’t see. I have been hopeful that things will be okay and that there will be no issues in the future but you know when you just have that feeling about someone? I’m having that feeling about the kid’s mom. Her grandmother on more than one occasion has told me that mom has been trying to start stuff because of my existence, the kids liking me, and us announcing the pregnancy. And the oldest child told me that mom said she wants to punch me in the face if she ever meets me (she clearly did not over the weekend). This woman has now asked to hold our baby’s after they are born because she will “have baby fever” and then hours later has her boyfriend messaging my boyfriend awful thing about both him and I. Am I wrong for just not wanting anything to do with her? I mean I know she’s going to be around in the future, but I’m so guarded with this woman, in my eyes her intentions are not pure with here own children so why would I think they are pure with our children? Babies don’t come till probably September so I do have some time, but am I just being overly dramatic because of the hormones or am I playing this smart staying so guarded? I think I’m mostly offended that she would have the nerve to ask to hold the babies as her asking happened the weekend prior so at that point I had never met her and all I knew was that she felt negative towards me though she is the one who left the marriage.