Everyone's good at different things Singing may be her thing, yours is just different. One thing about being good at something like singing or playing an instrument is that you have to "perform" for people all the time, and that can get tiresome. Instead of being jealous, try working on finding your own strengths

You say you can't sing? Wait till you hear me singing xD it causes strange responses from living organisms that hear it... o.O

If everyone could sing then the only job occupation in this word would be singers. I'm sure you have other talents that wins over your sister, focus on that instead. Jealousy can only bring trouble. 
I used to get jealous too, all my sisters were way more clever than me, I felt like nothing. But now I know I can do other things they can't. Have faith in yourself you are just as good as her, or even better. You just haven't discovered it yet.

I've noticed that when someone is paid, requested, etc. to do something, that tends to impress family members even more. I have a story. My parents say that I'm creative but they didn't make a big deal about a picture I consider my magnum opus. They know I'm not that great at drawing and such, but I found out I actually had a talent for coloring with water color pencil. And it was my first time using it and surprisingly my art teacher really liked it, because she was used to sucky work from me. Even the subject was pretty good (in my opinion); a pot-bellied mantis, a pot-bellied pig and praying mantis hybrid. So then next year in English we have do a project based around a book. I decide to just get it over with by creating a playlist and then relating the songs to the novel. My English teacher is impressed and asks me to sign up for a contest, which involves making a multimedia presentation. I do a little video with some stock photos, snippets of the songs, and brief explanations. I ended up winning in my category and my parents and teachers are amazed. It didn't seem to matter that it involved less creativity and talent than "Spanky the Pot-Bellied Mantis", I competed against one underclassman and came out on top. 

Me neither.

this is the best jelly ever!