It is just beginners that estimate trees age. Expert know that it cannot be done. Growth rate in different climates, different soils differs a lot. Pot size and pruning also make a huge difference. I have a thirty year old pine in bonsai pot 30cm high. In the forest around me the thirty year old pines is allready more than 10 meters high. The ones on the best locations and soil almost 20 meters.
In bonsai we aim at creating a tree that looks as old as possible no matter age.