Why do people upstage others pregnancy’s just bc they’re further along??

A close family members wife is a little over a month further along than me & keeps making up lies about shit to “upstage” me being pregnant almost. & she was the first one to say “oh well i don’t want our babies to be compared” but why would you say that when i had JUST told family i was pregnant & didnt say it to my face at that. It seems like she’s mad not all the attention is on her & now she’s trying to make everything about her🙄 i swore i wouldn’t get my feelings hurt but i am. She has lied to me repeatedly about stupid shit & then tried to say i was getting jealous (i asked how she got an ultrasound early since we use the same ob who told me she doesn’t do them until 20 weeks). Her first excuse was they couldn’t hear the heartbeat & then her husband (my family member) told me it was bc they had waited so long to see the dr the last time that she just let them get one. Like that doesn’t even make any sense to me???? This is a very close family member (she has this app so i don’t wanna say which family member but it’s in the immediate family🙄) so i don’t want to cut him off bc he hasn’t done anything but i can’t deal with her, they’ve only been married 6 months & only dated/MET 6 months before that. Not one family member who has actually met her has liked her bc all she does is talk shit & acts like she knows everything so it’s not just me. It bothers me bc she was there when i told both of my parents & automatically made it about her right after. I let her have her moment & she didn’t let me have mine☹️ the main thing I’m annoyed about though is her saying her husband has felt the baby move at 16 weeks even though she said she hasnt been able to feel the baby herself. So how is he feeling it before her??