Hi, congratulations!
“Rule #1”: ENJOY IT! You’ll only ever get your first gig in public. You will be nervous (the first 10 minutes) and stuff CAN go wrong. Don’t worry, nobody’s gonna shoot you and most likely everybody will think you did way better than you afterwards. Be in the moment and create a lasting memory of your first time.
As for the set, see if you can chop up your set in smaller playlists and have plenty of tracks with you (about double for the time you are actually playing) so you react better to crowd response. The small playlists prevent you from having to make the “what to play next” decision every track. Also you can practice the transitions in every playlist so it all comes out nice.
Hope that helps some.
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