How To Protect My Music

I’m a song writer … well actually a lyricists. I wrote a song for the family of a girl at my school who died in a car accident. Well the family gave it to a cousin who put music to it and sang it at the funeral. He’s recorded it over at a friends house and gave me a copy to hear how it sounds. Now there’s talk about selling copys of the CD for a couple bucks and have that go towards a scholarship fund in her name. I don’t want to be negative or a hinderance in any way but I just want to make sure that no one steals the song from me because it could be a huge step into a career that I’m interested in. I don’t have ANY money so I can’t pay to have it copy writed but want to protect my music. Does anybody know anyway to help me?