So I'm 16 and want to be pregnant because i have cancer.

I'm really not posting this for drama or arguments, I just want to get other opinions. I know a lot about pregnancies, test,fertility and other aspects I've been reading up and studying on it for 2 years. I even talk to my doctor about it. The reason I dont wait is because the doctor doesnt know how things will turn out for me.. my boyfriend and I have been together for four years.. Any thoughts?