Conversion

I am 17 years old. I have been raised as a Conservative Jew. I attended day school. Now that I am in college, I am going to Orthodox Shabbat services. I want to have an observant Jewish household and maybe make Aliyah. I would like to be able to date Orthodox guys as well. My problem is: 60 years ago, my maternal grandmother, who was not Jewish, married my grandfather. She went to her father-in-law and said, "I want to be Jewish." He told her that she had to live as a Jew. So she did, as a Conservative Jew that is, but as far as I know there was no conversion. The wedding ceremony was performed by a Reform rabbi. Do I need to convert, if I want to marry an Orthodox guy? How old do I have to be to convert? How long does it take? If I convert, will that be rude to the rest of my family, like saying that I do not think that my grandmother, aunts, mom, brothers, and cousins are really Jewish? Thanks for answering my questions.

Halachically, you are no longer a child and can convert if you choose to. I don't know if under US law you must wait to be 18 but I assume that an American Orthodox rabbi would know the answer. If your maternal grandmother was not Jewish and no Orthodox conversion was undergone by her or by your mother prior to your birth, you must convert to Judaism according to halacha. Try not to make your family feel bad, but it would be worthwhile for them to know that in order for their Jewishness to be universally accepted, an Orthodoox conversion is required.