in the future maybe bitcoin will be better and has a high price, so I would be good if I never sell my bitcoin and wait for the right time to sell
Never is of course not good because on a certain point you have to sell the bitcoin to make profit or simply spend it of course.
If you are waiting too long you will even lose profit and maybe even lose money because of this.
Holding bitcoin is a good thing but you don't have to hold that forever. You must set a range of years or length of time of until when you are going to hold that.
Because if you aren't going to use it or sell it, it is useless.