She's just realised she's in love with him.  She doesn't know whether to tell him, or not as yet. It's not an uncommon dating situation to be in! Here's a poem about this situation...

Last night, with you

Swept my doubts away

I feel like spilling

What I have to say

So thoughts buzz inside me

To find the right words

To speak how I feel

To let it be heard

And I want to call you

To let you know

I feel almost compelled

But I let it go

There's so many reasons

But do you want to know?

Should I keep it in?

Do I let it show?