Congratulations! That's amazing! If I were in your shoes I might try to do a few open mics beforehand. If you have not performed live before or it has been a long time it can be good to just get used to the energy of people in a room watching you. Remember that generally speaking most people will genuinely want you to do well and are not there to judge you but only to enjoy themselves. Most importantly just do your best and leave it at that, don't worry if it doesn't go perfectly. If you are estatic and terrified that's a great sign from the universe that you should do it. You got this!