How tall is the average 14 year old girl?
Varies from nation to nation and by ethnicity and many other factors. In the U.S.: 62.5 inches https://www.reference.com/science/average-height-14-year-old-375ae982bfe6f371
Tall enough so that her feet touch the ground
There is NO 'average' height for anyone. A person's height is determined by their family Genes.
4'2" or at least thats how tall my big girl is :)
5 foot 5
According to the CDC, in 2002 the average height for a 14-year-old girl is 63.7 inches (about 5 feet, 4 inches tall) - which is 0.3 inches taller than a 14-year-old girl was in the 1960's.
Probably around 60"/I50cm for a femal and mayb 65"/I65cm for a male at the same age although it dpnds what average you're talking about.
In which part of the world, with what ancestry, and under what general conditions of diet and exercise and medical care? And around early teens there is huge variation within any community as to how fast any particular girl or boy grows and develops in her/his body, so really your question has not much use in general.
Depends on your nationality. Thai women for example are much shorter than say British.