How can I get my state to legalize gay marriage/rights?

I'm fourteen and though I am only bi, my sister is lesbian and I find it appalling that Nevada dosen't allow gay marriage. So I decided to find a way to make it legal in my state, but.....I don't know how. So any advice would be much appreciated (please keep in mind I'm fourteen and trying to legalize a HUGE debate that somehow involves religion... my options are incredibly limited). Thank آپ and have a good day.