Should I start switch-hitting?

No way!!!! No you should not start switch-hitting. It will be a wast of your time if you start now. If you were 10 years old, then you would have time to work on it. If you are serious about the game of baseball, and want to go far with it, it's more beneficial to keep batting righty. Plus almost all switch hitters in the Major leagues started hitting lefty, and then moved to hitting righty. Trust me, it is way more easier to switch from lefty to righty than it is righty to lefty. All you need to do is focus on your right handed batting. If you start lefty now, that is taking away time from you improving your right handed swing. And since you are in high school (I hope), baseball is starting to get real competitive and you don't want to do anything that could damage your talent. And no, practicing lefty will not help your right handed swing in any way.