Hi! Im a soon to be 20 year old girl, and I still sound like a little girl. I don't mind it very much, but it also means that elder womens voices (25+) are very hard for me to do. I have a veeery tiny range. I've tried imitating voice actresses with more adult sounding voices, but I can only practice for about ten minutes at a time before my thoath starts to hurt, so I'm pretty darn certain I'm doing something wrong and that I'll damage my vocal cords in the long run.
So I'm wondering what way is best to increase my range without damaging my voice?