Yes it is normal for 11 year olds to like wearing diapers.
Many 11 year olds and older and younger kids love wearing diapers.
If you're the 11 year old who loves to wear diapers then you're not alone.
I've loved diapers since around age 5 and I used to think I was alone in my love of diapers but thankfully I found out I wasn't and still ain't alone after browsing the internet.
Here's a few pictures of a boy named Jarod who loves wearing diapers.
You can see more of his pictures by clicking the pictures or by clicking the below link.
https://www.imgvek.com/album/da13633ae11800954d4861a28ed0b7ec/Diaper_Boy_Jarod_Skateboarder
These pictures were taken in 2001 so he's likely in his 30's now.

