Should I be selling stock profits?

Pardon my ignorance here but please bear with me, I'm 21 and very new to investing though I invested some money into gold and it's currently up 1k, if I sell those profits I would make around 500 dollars profit as almost 50% of it is taxed at the end of the financial year. I was recommended to sell profits as it may just go down again but I would of thought that if gold continues to go up won't I make profits on top of the 1k profit I've made resulting in higher profits assuming it goes up? Can someone correct this please? Am I on the right track or am I dumb?