Why would my gf like my annoyingly deep voice? And why doesnt she agree with me that it is annoying?

I am 15Dont get me wrong i love my gf and im not pointing out my faults so that she will break up with me but i want her to agree with me that my voice is annoying. My cousin and my gfs sister agree that my voice is annoying. I get so irratated by it that i mite start cutting myself out of irratation. However, my gf thinks my voice is attractive. And so i told her that when im older im going to get voice surgery and change my voice. She says she will be sad the day i do that but i told her that she will thank me for it. So i rly wanna know y she would like my deep voice or in general why girls like deep voices