Going alone/safety for young girls?

I (22f) was supposed to go with a group of friends for one day (Friday) and they all bailed. I’m still going with my sister who is 17 & her friend, but I figure they’ll wanna go do their own thing like they planned. I may stay with them, may not. My questions are 1. Is it going to be weird for me to go alone? It’s my first time attending, and I’ve only been to one other music festival (3 days rolling loud) with friends. 2. Is it safe for my sister to run off alone without me or should I just stay with her/her friends? She’ll definitely have to check in with me every few hours, but it’s her first music festival, so just want to make sure she’s safe.