Boy's voices become lower and deeper during puberty because of a hormone called testosterone. As yoru vocal cords get thicker and longer, your voice gets lower and deeper. I was happy about it because I saw that now I am an adolescent. I grew very rapidly and was so happy. The first sign that your voice is changing is often a sudden squeak or cracking of the voice when you are talking.
Some boys find it embarrassing when their voice cracks, especially because it is so unpredictable.
Their voice will be normal one minute, but the next minute it is high and squeaky. Other boys do not notice very much when their voice begins changing. Even if your voice cracks a lot, don't let it worry you. Like other changes during puberty, it is perfectly normal.