The good news is that many people do feel awkward when they are meeting someone for the first time that they had been chatting with on a dating site. You are not alone there.
A way to go about feeling less awkward is to stop overthinking the date.
You are spending too much time thinking about the date and what could go wrong. Instead of thinking so much about the date, busy yourself with doing other activities.
The more you keep yourself busy, the less likely you think about the date and everything that could go wrong. This allows you to go to the date with a lot less pressure which in turn reduces the amount of awkwardness you feel.