I know this is probably a weird question but I am just wondering if it is actually possible for other people. I'm currently 15(and a girl) and my comfort zone is around the baritone voice type. Even my speaking voice is deeper than most people, and I've been trying to understand how this is possible in any way.
You can and (I hope) will sing wherever your range is comfortable. If it's where usual baritone or tenors sing, then so be it. What everyone needs to do is find the key for each particular song you want to sing. The key that suits your voice, for each song. It's not going to be the same key for every song, just because it happens to be D for several!
Most people have a two to two and a half octave range, roughly speaking. Some can extend to more, although the quality at each end may suffer. Karen Carpenter, I believe, had a four octave range - so could sing down where you are, but easily into soprano and more. Useful when multi-tracking!
Work with what you have been given, there are at least a million songs out there that will suit your voice, and if you sing in a choir, the lower register of your voice will always be welcome.
It's not all that unusual. Timbre is also part of the equation so even though there is some overlap between male and female voice ranges, "crossovers" in choirs tend to be rare unless nothing else could possibly work. In all-male and all-female choirs, the appreciated ranges at the "wrong end" tend to be quite more. Practice helps accessing registers and ranges that feel less natural and thus can make choir and ensemble work more accessible. For chanson-like solo singing, a low female voice responding well in chest registers will be very much sought after.
So not much to worry about, assuming that your usefully accessible range will, after training, be large enough to be musically useful.
There is an actual name for us: We are typically classed as contra_alto (not the same as alto). Generally that means female voices of tenor range but baritone included in this as well. We are rare, the lower the rarer and more wanted!
The alto typically ranges from F3 to F5, where tenor ranges from C3 to C5. A baritone generally stretches from A2 to A4.
Practice! Strengthen. Don't forget, you are young and your voice may still drop (girl voices drop as well, just not as drastically).
I can sing nearly a whole octave lower than in high school but my higher range is less than it used to be since I stopped practicing. If you want something flirty, there's always Nina Simone.
As a contralto i think of myself as a female bass with a baritone tessitura...e2 to A4, maybe a little higher on a day when my energy level is high and i can really employ power...most comfortable in third octave rang. I take lessons and have learned that with proper technique and the correct key I can adapt most songs to my range. I think power or air/energy and staying relaxed and just feeling the song is the way to approach the deep female voice...be confident with it...But it needs practice and its really best i think to work with a very good vocal trainer and learn music theory...you will need it to work within various keys..
Yes. It is not weird at all and that doesn't make you weird.
The way your voice sounds is determined by many factors but the size and shape of your larynx, neck and throat are the most important factors.
When I was in college one of the assistant professors was a female bass and sang in an all woman SATB quartet. I also sang bass in choir and sometimes she would sing in the bass section with us, lower than the baritones.
Her regular speaking voice wasn't that low, but definitely lower.
Hope this helps.