There are lots of time to reach 21 BTC. Bitcoin wont be gone tomorrow and it is here to stay for eternity as long as community have faith in it. So having the luxury of having BTC for a long time, I can say there are lots of time to reach that 21 BTC goal. Just work hard and focus on getting it and i believe everyone can as long as they do not stop.
Achieving 21 btc is difficult but not impossible, if we work hard and give our best efforts then one day we will be surely holding that amount in our wallet, constant efforts will help you in achieving that goal.