But then again, takes a year to take yourself to a level that you are able to make realistic animations.
Up to you.
But with no work, it will not happen.
What this guy said. But remember, realism isn't always good for video games. Using less sprites with more 'punch' to them instead of a pile of in-between sprites can make your game feel actually better. Animation can get into the gameplay's way, too. With 2D it's almost impossible to make really dynamic looking animation, so you have to be ready for jankiness here and there if you're going for really smooth animation.
Practice, fail, try again, repeat. That's how everyone makes their art.