How do I stop being a boring third wheel

Okay, so I finally made this amazing friend, and honestly, I'm so grateful. For the past year, I was really lonely I literally had no one. We clicked right away a month ago, but now I’m freaking out. Every day I worry that realizing that I’m a boring person. I feel like I have nothing going on in my life, which means I have nothing to talk about. I just talk about the same stuff over and over again and I’m scared of being friendless again.

Plus, whenever we hang out, her other close friend is always there. They have this crazy strong connection and they seriously leave me out constantly ):

My main question is how can I not be left out and how can I be a normal friend and actually talk