No one's good at first- I mean, look at Ado and Eve's first covers, and those are two singing prodigies- but you can always improve your techniques and find your style. A long time ago my music teacher told me ‘practice doesn’t make perfect, but it makes better’ and that’s hands-down some of the best advice I’ve gotten in my life. Practice alone won’t get you to where you want to be- practice and studying/researching will.
Sometimes you've gotta make a few Pablo Honeys before you make The Bends.
(some backstory on that quote: Radiohead's second album The Bends is regarded as one of the best albums of all time, but their first album, Pablo Honey, is... not very good. At all.)