Well, my thought on this is, People who believe in Bitcoin would always invest in Bitcoin, regardless of the year or the generation in which we live now.
So these calculation of years doesn't really matter for a newcomer in Bitcoin.

We just need to use the common strategy of;
- Buy Bitcoin when it's at a lower value and sell it when the values goes up

Buy >> Preserve >> Sell >> Repeat

With my personal experience, it doesn't take more than 1 year for the bitcoin value to up and down, so one year is just enough to earn a decent profit.

Atleast it's far better from what you could get from the interest rate from a Bank via. Fixed Deposit or so.

But always remember, never get tensed due to the Fall/Rise in Bitcoin value, just sit back and relax, it would be fine again in a few days or months, that's the real magic of Bitcoin.