Too anxious to date

24 years old, never been on a date before. Just matched with a girl from the gym that I've caught checking me out, shes caught me checking her out. Sent 1 message each yesterday and now I'm too anxious to respond because if things go well I have to actually follow through (which is so fucked up because I like her and it would be great if things worked out…). One of my biggest problems is I sweat excessively just from being warm and summer is just starting. If I'm nervous on top of that I'm going to have a soaking wet shirt. It's kind of a feedback loop as I start to sweat then get more nervous that its showing and sweat more. This seems like an unavoidable problem.

Then I just dont know what to do on a date or how to even get to that point since I've left her message for a day. Preferably I'd start talking to her at the gym but that's going to be at least a month and if shes being active on dating sites that could be a mistake