Not being able to physically go through puberty means the brain doesn't develop in certain ways that it should. Motoko turned out to be the serious and stern woman that she is because she had to undergo constant body and braincase swaps to adjust to the growth of her own brain and not be able to actually undergo puberty. Some of her emotions ended up being repressed.
It's quite normal for children to recieve a cyberization augment fairly early in thier life though (between 7 to 10.) Not being cyberized in the GITS world actually puts you at a severe educational and social disadvantage. It would be the equivalent of being Re****ed right now: You would require special education processes and have to learn slower simply because you can't keep up. This is actually one of the issues brought up in the Real Drive anime series, which takes place in the same universe.
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"A SMARTER hitman would have shot first..." - Major Motoko Kusanagi