Hey, as a 13 yr old here, I also do some of the same things you do. For speed and agility drills, try to get an agility ladder(pretty cheap) and try some variations to work on your footwork. As far as speed drills not being done outside, try plyometrics(can be done indoors in a larger space like garage) and sprints if you can get to an indoor facility. Stay away from distance running, doesn't help for baseball and also slows you down since you get used to training slow. If you have social media, try @adonis.harrison on Instagram. He posts lots of great pylometric exercises and exercises to get faster. Some of the things he focuses on is lateral quickness and first step explosion which are both great for getting to a ball and stealing a base. PM me if you have any more questions and good luck!