My mom is paying more attention to my sisters pregnancy and very little to mine

Idk if it's because I'm hormonal and emotional but for starters my sister and I do not get along what so ever . She's 17years old rude and abrupt and very selfish . I announced my pregnancy shortly after my 11th week . 3 days later she announced she is 17 weeks pregnant . I come from a religious family where premarital sex is very uncommon and looked down upon , but surprisingly my family took her pregnancy well . Sure my father was upset blah blah blah and I was upset thinking she pirposely announce it to steal my 15minutes of fame . Which hurt . I won't lie , selfish of me but it did . I know she needs more support them me emotionally, but she envys me for "having it all" married house cars but what she doesn't understand is that to me that doesn't count . What she doesn't see is that SHE has it all . The first grandchild spot, the support, my mom accompanying her everywhere for dr appts ultrasounds etc . At first it didn't bug me I said it's ok she needs my mom more than me , I can do this by myself . My husband has a great job and works long hours hence the money we make that my sister apparently thinks is a priority and has declared her jealousy on it . What she doesn't get is that she stole my mom from me . I can't ask my mom questions cause she's always with her every where we go she's there , my sister doesn't speak to me at all she ignores when I speak to her so we just don't communicate . Every time.i ask my mom something or try to tel her about my dr appt and the baby update my sister shoes in and interrupts me and changes the subject . The sad part is that lately I've felt my mom distant . Like she's allowing it . Like she's suddenly grown some anger my sister has for me from her . I don't understand it and I feel so alone . Every time my sister asks my mom to go to target to look at baby stuff or anything baby related and my mom drops everything to do so . But when I ask she's always too tired and says to me "just take my van" I have my own car if I wanted to go by myself I wouldn't have asked .  I feel So extremely alone that I had to ask my godmother to accompany me to my gender ultrasound since my mom is always busy with my sister or tired from their adventures . Am I in over my head ? Am I selfish? Am I wrong ?