You can consider that bitcoin will meet halving event at May on this year.
Seeing the history when bitcoin has met halving event its price will drastically increase.
So, there is no doubt to pick bitcoin and you can enter it to your portfolio.
Entering bitcoin into a portfolio is the right choice because we know that bitcoin is a coin that has the potential to provide a large profit for those who hold the coin. But investing in some altcoin is also a good choice if we can look for opportunities from a coin that has great potential like Ethereum for me is a very good coin to invest and when bitcoin prices increase I think the price of altcoin will also increase later.