Hi Val
Never mind what her issue was, you can't look inside her head, so she had to tell or not, but it's nothing you should worry about.
It's not your job to relax her, it takes two the tango.
Just be yourself, enjoy the meeting and don't have high expectations.
Just see how it goes and take it as it comes.
It's only a first meeting, just a nice talk and enjoy the food.
If it was nice, you can make a second date, if it wasn't, say farewell.
one day you will be lucky and you'll meet a nice person.
hugs
Annette