Catholic marrying a Muslim, should I convert???

Megan
So I am a Catholic and my boyfriend is Muslim, his family are religious and my family have always been strong Catholics. I was raised as a catholic from birth being baptised and having my holy communion. Now that me and my boyfriend are speaking about kids and marriage his younger sister who is very religious has started speaking to me about the Quran. She is telling me that at the end of the world we are all going to convert to Muslim, if I marry my boyfriend without converting then I will make him to straight to hell. She has told me that I have the option to either convert or just stay friends. My SO has never ever raised the issue with me and has always been fine with my religion. I feel like his sister is pushing me deeper into being a strong Catholic. What would you do???