I'm a good singer, but my sis claims she's better. I KNOW i'm better. What can I do? Please help!!!

Just ignore her. I know it's hard, (trust me, I grew up in a house of 7 kids) but sometimes it's what you gotta do. As long as you have confidence in yourself, that's really all that matters.

But, if you're serious about proving who's better, you could have a contest. Each of you sing to a randomly selected friend/relative and let them decide. Or, if you don't like singing in front of people you could record yourselves.

There is really nothing you can do if someone is being immature in that way. Ignore her. You have nothing to prove.

Do a singing contest to know which one's better. Or record both of your voices singing and judge which one's better.

have a singing duel challenge her have your friends and family choose

Just say "You know what! That is super mean whether I am a good singer or not! How would you like it if I called you a bad singer or said you sing of key?"

Have a contest, and let who eva is watching decide! prove yo sis wrong and show off yo talents!!!!

Don't fret! No offence, but it's just a voice! It doesn't matter who's better, what matters is that you're both awesome in your own unique way!