I like her, but should I let her go?

A few months ago I met Katy. She was and currently is in a polyamorous relationship with 2 other people (both very long distance).

Shes made it clear to many others (including myself) that she’s not interested in another partner. That was completely fine. However, during the last several months we have grown much closer. I invested my time into Katy because I genuinely just liked her as a person and it seems she also feels a strong bond with me. Recently, she’s been hinting that she wants me to join into her relationship. Very obviously actually.

But in truth, I don’t know what I want. I have never been in a polyamorous relationship and I’m not sure if I have the maturity for it. I also don’t think I’m very smart and Katy is so very intelligent. I know the more she gets to know me the more disappointed she will be. I’ve already shocked/disappointed before about not knowing things.

My hesitance on the situation has left me feeling very aware of other people who try to get closer to her. Recently, a new person (can call him b) has been consuming her time. Of course Katy still tries to message me everyday but I just haven’t been answering in depth (mainly because I don’t know how to reply to her topics due to my low intelligence ahaha). It seems Katy is starting to grow a bond with B since they’re both smart. I can’t stop it.

So, I’ve been planning to just let it happen and see. I can’t stop Katy from loving another who genuinely seems like such a good fit for her. She seems happy. In the meanwhile I’m reading and learning like crazy so I can understand what she loves better and grow my self confidence. Truthfully, if she starts dating B, that’d be too much for me. I wouldn’t date her since a pentuple seems like nightmare fuel.