Hey there! Congratulations on your first date! That's really great and I am excited for you!
I guess my advice would be to not go into it with any expectations of what might happen. I have found that having expectations makes it hard to enjoy the date if things are not going the way I pictured/imagined/wanted them to be. Similarly, I would also suggest just being in the moment. I know it's easy to get caught up in your head, try and think ahead, but just focus on what's going on in the present, here and now. Focus all your attention on her, what she's saying and doing. Truly enjoy the feeling of being outside, and savor the food you are eating. I know it might sound corny, but focusing on being mindful and present is actually a good way to fully enjoy your date to the max.
In terms of physical contact, I would try and follow her lead on that. When you're in doubt, go slow and take your time. Jumping into more affection than she is ready for is a surefire way to nip this connection in the bud. Remember, consent is sexy. Ask before you make a move. Some people might say that's not romantic, but honestly consent is super key, and I can say from experience I like it more when my date asks me before making physical contact.
I hope this helps. Good luck and enjoy your date!
PM me if you have any questions!