Wear whatever you have that you think make you look the nicest and makes you comfortable, then forget about it. If the choices of clothes and words you speak work, then the shidduch is still a go for potentially a 2nd date. If things don’t fly, then the shidduch isn’t a go and you guys call it quits. It’s really very simple so don’t worry about it. There’s no right or wrong here. Just relax and basically the date will go in one of 2 directions.
Take 2 or 3 minutes to say 2 perakim of tehillim before you go out. I know you have a million things to do now but tefillah for a couple of minutes is a wise thing to do as well. You’ll get all the help you need from shemayim and won’t have to reach out to the coffee room for help if you do.
If you do go out again, you might want to print out all these answers and read them to the boy for fun on a future date.