Your speaking has very little to do with your singing voice in my opinion . I speak much lower than I sing in general . So that has very little correlation in my opinion . As a 13 year old , your voice will change significantly . I mean at 13 I was able to sing an A 5 very easily and resonantly . Now I can only do that if someone has punched me and I am in pain or with a ton of helium . haha . That being said , singing is like a muscle , you do need to practice it to keep it sounding a certain way . I would say it is a split . When I was 1520 I sang baritonebass . When I got into university , I sang tenor 1 lines and now my voice is much stronger in the tenor 1 than it is in the bass range . That being said I can still sing bass fine . just not as well as tenor lines . Hope that helps