That time was right time. Btc and altcoins were low, so buy low which could be the perfect example of buy how and sell high rule but this time is also Right time cause we are possibly facing the start of bullish phase. And there's no need to worry about big dump but market could face dump during btc halving which is a possibility. Otherwise everything is okey. Please not that, this is my personal option. Nobody surely know when what will be happened. Crypto market is always risky but gaining percentage is also higher than others
Apart from bitcoin, all the investments made on other cryptocurrencies are a double-edged sword, yes it has more probability to increase when the bitcoin becomes bullish but it doesn't necessarily mean every crypto will rise too, so pick the coins that have more possibility of rising generally coins with high marketcaps will be the preferred choice.