Bitcoin is still under $30k and still above $20k, of course it's not too late,
if you are still in doubt, maybe you can buy bitcoins or altcoins by accumulation,
so that the risk is smaller and of course make sure you have to divide your capital and don't buy 100% of bitcoins or altcoins .
I would say that investing in altcoins in current market condition is not a good move because the altcoins can drop further in value if the market doesn't recovers fully. I even think that altcoins will see more than 50% dump if Bitcoin dumps once again, and there is little to no chance of their recovery in coming weeks after the dump. In such times one should be more cautious when investing money on altcoins. The only altcoin that could be profitable in current market is going to be Litecoin, but still invest in it at your own risk.
On the other hand, I think it's the best time of the year to invest in Bitcoin because even after so much pressure on the crypto market and the exchanges, the Bitcoin's price is stable at around $25k, and anyone who buys it at $26k or less, will have quite good returns during the next bull run. The Bitcoin is the king of the crypto-currencies and it will cross the range of $120k in the coming bull run, so anyone who's into Bitcoin will have good returns within a year or two.