Get together : friend [21F] planning a reunion with an old friend of mine [19F] and wants me [21F] there.

Okay let's start with names. Let's say my current friend is Tammy and my old time friend is Sarah. Tammy and I are kind of close but she's the kind of friend I like to keep my distance with because she is extremely extroverted, noisy, and doesn't have a funny bone in her. That type of energy for a long period of time wears me down.

Tammy was out of the country for a while and just came back last year. We Skyped every couple of months to check up on each other but I never really considered us to be close. She came back and got a place a couple of blocks away from where I live. Lately we have been texting and we hung out a couple of times. Now she texts me and says that she bumped into my high school friend Sarah. Me and Sarah kind of disconnected totally after high school because we never had much in common but primarily she was going through a very rebellious phase in her life so I wanted to stay away from her. Also she never contacted me so I just took it as a mutual sign that we were probably not the best for each other at the moment.

Tammy didn't go to the same high school as me and Sarah so she never really knew Sarah well. But after something scandalous involving Sarah broke out she pressed me for info and then she reached out to her. Tammy has a tendency to be very noisy and she likes to befriend all of my friends which I usually don't mind that much. But now she's sticking her head where it doesn't belong. 3 years after the scandal and 6 years after I last spoke to Sarah, Tammy bumps into Sarah. Then she invites her over to her house for the weekend. And texts me to come over as well since I used to know her.... Idk I just really don't feel comfortable starting a relationship with Sarah of any kind. Even Tammy, I believe I should distance myself from. I don't wanna go, but I don't wanna be rude. Maybe I'll go and try really hard to not exchange numbers. I don't wanna rekindle a relationship with Sarah. I really don't think she's good for me. And I don't have the best of memories with Sarah. Feel like back then I was a totally different person in high school and right now the amount of change I've been through is so tremendous. I know I won't have that moment where it feels like we have never been apart. tl;dr Was invited to a reunion with someone I don't want to see right now or start a relationship with as I know our differences are just too much but I don't wanna be rude.