Being aggressive on the bases is fine at 10U, as it is hard to teach the girls to take the extra base when they are older and haven't done it. However, being aggressive and then yelling at the player for getting thrown out is an approach that will result in a very non-aggressive base-running team. As a coach, you have to be willing to take the hit for the outs when you send the runners.
If you don't tell your kids, "If you get thrown out it's my fault" then you're doing it wrong.