Ultimately, you bet it matters....
Now, please note that I do not personally care whether these are your adopted beliefs or not, or whether you choose to play by the rules or not, that's not my business but it's certainly your prerogative. However, you can not say that it doesn't matter whether Jesus died on the cross or was born of a virgin or not. Jesus Christ wasn't "just" a teacher and he didn't come to find "followers" for his teachings. His teachings are completely secondary to what he actually came to do. His mission was to rescue man from their shortcomings and offer them a way to get into the Kingdom of Heaven, and to do this, he needed to be a human in bodily form and be born in a way that would be different from all other men. This could only be accomplished by being born in a supernatural fashion and offering up his body as a sacrificial atonement. Christianity is all about the atonement, and the atonement could only be accomplished by his death. (All the reasons why beyond this are foundational basics, but I'll spare everyone who isn't interested from hearing the details.)
I can certainly understand it if you find this hard to believe, but the whole belief system hinges upon precisely these very two facts. If you take them away, you have some kind of belief system going, and you may call it whatever you like, but you couldn't rightly call it any kind of christianity. They are centric to all denominations and persuasions.