Meeting his sister

I’m pretty sure I will be meeting my boyfriend’s sister for the first time later this week (pretty sure because though he hasn’t said it, has basically hinted it) and nervous is not enough to describe how I’m feeling. My boyfriend and I get on really well and like each other very very much and he is so close with his family and his sister (his only sibling) so their opinion of me is very important to me and I’m dying for them to like me. I have never met any of my bfs family members before so this is just new to me, besides this I am a very awkward person and it takes a while for me to warm up to people. Any tips on alleviating this stress? I’m sure she will like me because from what I’ve heard we’ve got a lot in common but I am just super anxious about this.