So for someone background, when I (30F) was 18, my mom gave me a ring she had gotten from her grandma. It was a family heirloom that has been in our family for decades from female to female, I don't even know for how long. Now, I barely wear the ring myself because I'm too afraid of losing it or have it stolen, so I'm keeping it safe most of the time.

Last year, my partner proposed to me and I said yes. The wedding is planned this year, and it would "officially" mean I'm part of their family and he is part of mine. These events have got me to start thinking, what would happen if I die? Who will get my stuff, including the ring? Who do I pass it onto? We are not planning on having kids, meaning I won't have a direct child to pass it onto. Now, my fiance has a niece who is still a kid. She is the oldest kid within both our families. My family is relatively small. The bond with my niece isn't close. Mainly because she's a kid that dles her own thing. Even at family gatherings the children are playing with each other while the adults are hanging around together. I completely understand that, and I don't blame my niece one bit for not really feeling the need to get closer to us. That being said, it made me wonder: do I have to pass on the ring to her when my time has come? It would've been continuing the tradition of the first female getting the ring passed on (I believe my great-grandmother who gave it to my mom only had sons), but it just doesn't feel right to me. I barely know the kid. I know it will probably take a long time before I will eventually pass, so maybe I'm just overthinking things. My inlaws don't know anything about the ring anyway, my fiance does though. I also have a younger brother (28M) who has a girlfriend. We have met her a few times, and my fiance already predicted that if they would stay together, they will most likely have kids. He does see my brother's gf as that type of girl. Now, the idea of passing the ring on to a child of my brother seems more tempting to me than giving it to my niece. This is once again still hypothetical since they haven't even have kids yet, nor do I know what my bond with them will be IF they decide to have them. Does that make me a hypocrit or unfair? Am I just overthinking this? I have talked to my fiance about what would happen to our belongings if one of us will pass away. He said that my belongings are mine, and it is my choice who I pass them on. That made me feel better, but I'm still wondering. WIBTJ if I would prefer passing my heirloom onto a bloodrelative instead of one of my inlaws, despite my niece being older?

Update/edit: thanks for your words and comments! I do understand that the ring is mine, so it will be my decision who will have it after me and that it will be ok if I decide to keep it in my family. I was just overthinking it all, but this helped me too. Thank you guys.

Update 2: Wow, I didn't expect so many reactions! Thanks again for your responses, some had beautiful stories, others had some good advice I can use. Setting up a will is something I think I'm going to do. Not that I expect to pass away soon, but just in case. I'd like to make clear that my future husband is supportive of whatever I decide, other than that none of my inlaws know about the ring.