What Bob said. You need a supportive coach.
My right handed hitter used to practice hitting left on his hit-a-way tied to the basketball goal in the backyard. He would switch from right to left ALL THE TIME just playing around. One of his travel coaches at 13 said to go ahead a try hitting from the left side, but you can't go back. He didn't do it. He kept hitting right in games.
Then later another travel team/coach gave him the go ahead to switch hit. So he played around with it. He didn't hit as a switch hitter early in HS basically because he wanted to make, and be successful, on the Varsity team. He was at WWBA as a rising junior (with the supportive coach), turned around at his at-bat, and hit a bomb from the left side. The coach of the school that he eventually committed to just happened to be at that game.
So in HS he started to switch hit as a junior, switch hit all through college, and was drafted as a switch hitter. They haven't converted him back...yet.
The down side....son said during recruiting some of the bigger schools with bigger programs weren't convince he was a true switch hitter and passed on him. He eventually went to a high academic D1.
Parent fail: I kept taking the spoon out of his left hand and putting it in his right at a toddler. What did this mamma know about baseball back then!??