8 Month old wearing size 6 diapers?!

Vanessa • Married to the most wonderful & handsome man in the world! 👧🏻💞 born Oct. 23. 2016 & 👶🏽💚 born May 2. 2018 ♥️IG: DwyerBearFamily
Update:
Hello Everyone! My almost 8 month old is wearing size 6 diapers. I read a post of a lot of babies wearing size 3 or 4 her age. 
Any size smaller will leave red marks and indents on her butt and around her legs.
They barely strap on at a comfortable tightness.
As you can see in the picture below she is not a really heavy baby. She is a chub chub though and doctor did say she is higher in the percentile for her length. Any thoughts?
 Thank you!
According to Huggies here are the signs the diaper is too small and you need a bigger size:
1. Frequent Blow Outs
2. If your baby has red marks along their thighs 
3. If you are having difficulty connecting the diaper tabs at your baby's waist. A diaper should close easily without having to pull at them.
4. Is the rise of the diaper just below your little one's belly button? If it fits more like a low rise, it's time to move up!