When my three-year-old asked me recently why she couldn't reach something, I said it was because she was too short, and she responded, "Mommy, you're long!" I corrected her, saying that I was tall. (At 5' 1" I'm not, really, but it's all relative.) However, it's valid to use "long" to describe her little sister, who's less than a year old and can't yet stand reliably. When she can, will we go from describing her as "26 inches long" to "26 inches tall"?
It's interesting to see what terms they use in other languages. Spanish uses bajo and alto, literally "low" and "high", while German uses klein and groß, or "small" and "large". The words for "short", corto and kurz respectively, apply only to things like pencils...and babies? I'll have to consult some experts to answer that question.