It's always the best time to build some assets into your bag, you can just pick whatever in top 20 of coinmarketcap and you can call it a day, just make sure to do research first because even though it's a top rank altcoin on coinmarketcap it doesn't mean you can always jump right into it, you have a risk to jump into wrong times and losing your money.

It's possible, but rather difficult to make it dip like 2018. It was a disaster and make more people have negative impact to Crypto in general and made the price continuously decreased for quite long time. Since we are close to halving, I think we won't see that happen in quite long period of time.