It's also inaccurate. The Constitution has been amended 27 times. It has seen 33 amendments sent out for ratification. The Constitution is 227 years old, give or take. it's an oversimplification to say that it gets amended once every 8 and a half years (or 6 almost 7, if you want to count the 33) but the idea that it's A) actually old by any decent stretch of history or B) totally immune to change is, you know, pissing in the wind.
And that's before you get into the rest of the discussion around interpreting it.