/ic/ - Artwork/Critique

Hi, I don't draw very often but I do a bit. Everywhere I read that adult humans are eight heads in proportion and teens around seven. What happens to me many times is that my drawings tend to hover around six heads (or six and a bit) and I read that six heads is for characters below ten years old. Ignoring the flaws that come from my lack of experience, many of my character drawings look pretty much like teens. Is there something inherently wrong with six heads proportion when drawing teens? Does it look okay to me because they're just standing, they're manga or because I am being indulgent with myself? Do they look wrong (proportionally speaking) to you?
Also, any recommendation for these specific cases?
Sorry for the quality of the pic

Hi, I don't draw very often but I do a bit. Everywhere I read that adultos humana are right heads in proportion and teens around seven. What happens to me many times is that my drawings tend to hover around six heads (or six and a bit) and I read that six heads is for characters below ten years old. Ignoring the flaws that come from my lack of experience, many of my character drawings look pretty much like teens. Is there something inherently wrong with six heads proportion when drawing teens? Does it look okay to me because they're just standing, they're manga or because I am being indulgent with myself? Do they look wrong (proportionally speaking) to you?
Also, any recommendation for these specific cases?
I don't usually post here, this looked like a good place to ask, please excuse me if it is not. Also sorry for the quality of the pic