Well kudos to ya. However, in case you noobs might not remember, what we're experiencing now is eerily similar to the dot.com bubble of the late 90s. So keep that in mind and be nimble and tread carefully.
You are just one of a large crew on here who have compared this bull at various points to the 1990s and mostly been wrong every single time. And the reason is simple, you need to look at actual performances and actual fundamentals to do a proper comparison. Any time I brought up REAL metrics years ago on here people ignore them and prefer an emotionally based will to crash the market.
Dot com companies had far worse fundamentals and the Nasdaq went up in 1998 similar to this year's performance. So one has to ask what might occur in 2020 if you feel the 1990s are instructive. 1999 was the best year to be long the Nasdaq in history. I don't see anyone warning the bears on here. Funny how that works.
My point, you are too early and overstating the nature of any valuation issue. Without a true catalyst to crash the bull, it won't. In fact, 2019 was one of the easiest years to make money IF you didn't trade/invest emotionally.