Right now Mount Everest is about 29,035 ft and growing at the rate of 2.6 inch per year.
Naturally, the ways to determine the age of Mount Everest is to divide the height, i.e., 29,035 ft, to 2.6 inch/yr and that would give you the age at 134,007.69 years from flat to the peak. If we follow this theory then we could say that the Himalayans used to be like a flat deserted piece of land or like the Sahara desert, or maybe hundreds, or thousands of feet below sea level. If we follow the creation of earth in Genesis around 6000 years ago, at the rate of 2.6 inch/yr it would have grown only about 1,300 ft or at the beginning of the creation Mount Everest height is at 27,735 ft plus 1,300 ft of growth = 29,035 ft.
And you can apply the same principles or analogy or whatever idioms you want to stalactite and stalagmite.
Were they here or formed already when God created the earth? Yes! And when man started observing their growth, with simple arithmetic, all theories about the age of the earth came out, some are saying billions of years while others hundreds of millions of years. Where is the proof? NONE!