Getting nervous

Hey, all. I’m pregnant with my third and I’m suddenly freaking out. My son and daughter are only 19 months apart and they are absolute besties. I’m so concerned this baby is going to totally change the dynamics of this family and come in between my kids. I love their relationship. My son is the oldest (4), his sis is 2.5 and we’re expecting another little girl. Has anyone ever had a similar set up and their two stayed best friends? I also don’t want number three to feel like she has no one and I’m 37 so I’m not sure there’s another one to be had after this one. Is this baby going to destroy the bond between my older two or feel like a total outcast? I’m the youngest of three (only girl) and although we are close now, I always felt like my brothers didn’t like me growing up. Thanks for your stories 💕 I know three can be a tough number.