I lied multiple times to my sister for touching her stuff
Why did you touch her stuff to begin with?
She was acting like an asshole to me, especially when she threw away my toys without asking me.
You should still tell her the truth! I know it sucks but an eye for an eye makes the whole world blind. You should talk out your problems before retaliating and lying about it.
I don't feel like it and fuck it, I am glad that I did it.
You can decide not to tell her, but if she was to find out later, things would only be worse.   Telling her now gives a better chance of avoiding later drama.