Do you think the stock market will crash in 2021? Please explain why?

I still bullish about 2021. But i wont be adding more position now as the s&p is overextended, far from moving average. Uptrend doesnt mean go in straight line. Expect 10%-15% retracement from current price

Regarding your question, there really is no way to know unless someone has a crystal ball. Anyone who tells you otherwise is a liar.

Will it crash again in 2021? Maybe? What if there's a mutated form of covid, what if another virus shows up? Oh the other hand, what if the vaccine have protected most people and the economy is booming again. Lots of what-ifs.

Regardless, I believe it's just best to hold good and strong companies that continue to grow in good or bad times. DCA if you need to and it'll all be fine. We can't predict the future, so let time in the market do it's work.