Whatever decision you make are both good. Holding bitcoin is also a good thing to do since the value of bitcoin now a days is fluctuating to high. If you hold bitcoin for a long term investment then I can say that your patience gives you more profit at the end. On the other hand, if you sell bitcoins and you decided to buy altcoins then make sure that you study first the reputation of the altcoins that you buy so that your investment will grow until the end.