Hi Phinnweb
Your voice should start changing anytime now.
I would think you have not done any damage to your vocal cords because of your habit of talking in a high pitched voice around your parents.
It could be that under certain circumstances your high pitched voice is what comes when you’re nervous and maybe you just have a bit of a naturally higher pitched voice.
The best things might just be to speak in your natural voice and tone whatever that is all the time and that includes at home with mom and dad.
They know their boy is going to grow up and the changes that happen along with growing and developing will take place as well.
Try getting into the habit of using your natural voice and tone all the time, avoid trying to deepen it at school or with friends and stay away from the high pitched mom and dad talk use what comes out naturally and see what happens.