I recently learned that I have too much testosterone in my body and my dad is trying to get me into the hospital because he wants it to be lowered. I'm really worried because once it's back to normal again, what will happen when or if I decide to take T-shots. Will I be put in danger again (because I'm told if nothing is done now I could die), or will it everything be fine? Does anyone have any advise?

I've never heard of a female dying simply because she has too much testosterone in her system.
There are certain things I know it puts you at risk for and they could eventually kill you if something serious develops, but I don't see why you are in extreme medical danger right now from the minor details you posted. I actually have a few cisfemale friends with naturally high testosterone (ironically they are both ultra femme and don't look masculine at all) and the main problem both of them have is that they have cysts that developed inside of the walls of their female parts. They are at higher risk for developing cancers and one of them has been told it is unlikely that she will ever be able to have children - this girl is in her early twenties. Are these some of the things you are at risk for or are they telling you something else?

I'm not sure what they have to do in order to lower the testosterone in someone who is AFAB, but I assume it has to do with taking estrogen or some other female hormones.  If you did this, and then decided to take T they would most likely take you off estrogen, wait for that to clear out and then do bloodwork to get a base level of what your body's natural T level is and assign you a T dose accordingly.