When is a boy's hair too short?

Hello everyone, my name is Valinda and I'm a newbie to this forum (this is actually my first post), which I found accidentally while browsing the internet. I am a single mom and live in Texas, where I have an 8 year old adopted black boy (not bi-racial). He is adorable and has been the greatest joy of my life. My question to you mothers of little black boys is what type of haircut do you give him? I am currently having Curtis where a "zero" cut, which is basically shaved almost clean with clippers all over his head. It looks like someone drew little dots or sketched hair on his head. After experimenting with different styles and lengths over the years I have found this to be the most manageable look for him because his hair is extremely course (nappy) and therefore nearly impossible to comb or brush with him still looking presentable. I think he looks very sharp, nice and neat if you will, and I often receive compliments from others on how cute he looks. Where I live it stays relatively warm all year so this is his standard look. I am posting this thread because recently a white mother of a bi-racial child at my son's school (I'm Hispanic) questioned my decision to cut his hair so short, in her opinion, saying he was "bald-headed" and little boys shouldn't be bald-headed. My son's teachers have no problem with it and nobody else has ever confronted me about it until now. But it made me wonder, when is a boy's hair too short? Also, based on how I described my son's haircut would you consider him bald-headed??? I thought only men who shave their heads with a razor were considered bald-headed but I guess my son could be included in this description as well, I just never thought of him like that until now. Any feedback or thoughts you can share on this would be greatly appreciated and I'm very happy to be part of this forum!