I feared new altcoins will be left out so i start selling some coins for bitcoin because it can be a big blow if altcoin fails to surge like in 2017 after bitcoin reach a new ATH, what do you think? And what would you have done in my position
I don't want to sell my token. My experience was "Thinkcoin", During Bitcoin touch 13000 USD, thinkcoin did great bullrun. Altcoin price will change after Bitcoin halving. This two ways is profitable, swap Bitcoin or other coin could safe than old coin.
Most altcoin will experience the bullrun but there are very important features you need to compare before making the decision to hold the token you have in possession and i will advise you to compare the coin you mention features and level of support when it was launched to those you have now.
Meanwhile, if you sell your token for BTC now you'll even make more profit through BTC than the token.