Helppppppppppp !!!

Siera • Siera 🙋🏽Engaged 💍 20 🎂
Okay so me & my sister in law got pregnant 2 months apart . I was ahead of her my baby was due in July & I was blessed with a girl & she was due August & was blessed with a boy . During our pregnancieswe shared everything ! I hated it . This was my first child & I didn't even get my own baby shower & she always try's to be better & compete with me . It's annoying & gets me so mad ! 
My daughter ended up coming in June instead of July 
Her son still came as expected in August . The reason why I am writing this is because now she dies it with our babies , always tryna tell me how more advanced he is :/ 
So Her son started to get teeth at 3 months get got both his bottoms at the same time at 3 months .
Today my daughter is 8 months STILL WITHOUT any teeth 
So I'm writing this to ask you other Mommys what ages did your babies get their teeth & is it normal for my daughter to still not have any . 
My sister in laws son is now 6 months , still with only those bottom 2 teeth he got at 3 months old .