It's never too late to buy BTCitcoin. The price should go up as long as we didn't acquire yet all 21MBTC, the demand for BTCitcoin will surely become higher as we approach the 21MBTC mark.
By the way we are at 16.7MBTC as of October 2017.
How exactly do we check this, i.e. aqcuisition of BTC. Moreover is this kind of some bench marking.