For the "bro shes 10" person
The demi-humans in the show become instant adults when they level up, so the time from her birth is irrelevant. Elves (in fantasy) would be the opposite example as they are still children in their 60's. One person is an adult at 10 while the other is a child at 60. You can't use human age standards on non-human characters.
Now that that is done, it does look really well made though $330 is a bit much to part with as I don't have much excess income. If I was going to spend money I would get the "Hot Spring Ver. 1/7 Scale Figure" as that one is more appealing to me.