I am 18 and I sound like I am 14. When I was 14 I sounded like I was 8. I am a soprano and I have good technique and a pretty powerful voice when I sing, but the tone of my voice just sounds like a little girl. (My speaking voice sounds pretty young too, but not as young as when I'm singing) Other girls my age have voices that sound much more mature than mine. It's like they hit some type of vocal puberty that I have not hit yet. Everyone I sing with thinks I am younger than I actually am (even my vocal teacher). Is there like a biological reason why my voice sounds like a young girl?