I'm a teenager with a large clical voice, but when I sing "correctly"...?

I sound like I'm 40. I'm not doing this intentionally, but when I relax my tongue and round out my vowels I seemingly age my voice 25 years. So, when I perform I take steps to lighten my voice, and that I have to do intentionally. Is it possible for a young female singer to have a naturally matronly voice? What should I be doing differently?