What takes away anyone's right to decide what God wants? You? As long as there's no coercion or violence, what someone else thinks of your relationship with God is none of your business.
Thinking or believing what you want is not at issue. DOING something based on that belief IS. For the record, I can assure you that no Jew with any grounding in Jewish beliefs, practices or traditions actually cares what you believe - we only care what you do about it. Oh, don't get me wrong, we'd certainly like you to at least abide by the 7 Noahide laws (which I think that Christianity pretty much covers), because we certainly have nothing against you all attaining a place in the World to Come (what you'd call "Heaven"), but your beliefs BY THEMSELVES don't affect us very much. But we are also rather keenly aware of the history of our own people, and these things (which ALWAYS start as a polite discussion) are never viewed by Jews in a positive light - see below.
You are clearly not very well-informed (at least not based upon that line) about the history of Christian attempts to convert Jews. In the interest of time, I'll give you a really condensed version: it NEVER ends well for the Jews, and occasionally the hatred generated in the Christians by the Jews refusing to give up their faith leads to oppression, expulsion, asset seizures, massacres and, sometimes, attempts at genocide. The last such attempt at genocide is still within living memory, and before you say, "but the Nazis weren't Christian, they certainly didn't ACT in a Christian way, they were pagans" (which, btw, is correct), let me assure you that without the constant drumbeat of anti-Jewish official teachings, literature and actions on the part of Christian authorities, what the Nazis did would not have been possible. Perhaps if you understood that, REALLY understood it, you might understand the lack of an open mind on the subject by Jews.
Oh, FYI, people saying (out of sincere and well-intentioned belief, no doubt) that "salvation is only through Jesus" is not very philosophically far from "if you don't believe in Jesus, you're going to Hell." That is not very philosophically far from "OK, let's get rid of all of those who are going to Hell." You may think that the last step is a big leap (and, hopefully, for you and everyone else in the world it IS), but history shows otherwise. That is why we Jews are a bit touchy on the subject. Read your history, in addition to your gospels, and maybe you'll have a better appreciation of that.