I need help with first date

Hello,

I'm a 19 year old male and i have contact with a girl i used to like a few years ago.
We haven't seen each other in years and now i'm going to see her.
I'ts a little bit weird but she is going to leave town to go somewere (private reasons) and i just want to see her before she goes.
So i told her i meet up with her at the train station.

I have always had problems with girls, i don't know what to say and how to keep a conversation going.
How a girl will react on things etc.

I'm probaly going to see her for a 20 minutes or so before she hops in the train.
How can i start a conversation with her and how do i keep it going, what type of stuff can i say to her?

Thanks bonfire, a things i have to say, she is leaving town for a week due reasons that are personal.
She leaves for a week and comes back next weekend, this goes on for a long time so i can only see her in weekends.

I wanted to see here this weekend but she was to busy with school stuff and all that due personal reasons.
So i just want to say goodbye to her and talk with her before she goes again for the whole week.

How can i start a conversation and what type of things do i say to her.
I'ts my first time seeing her again in years.

Yeah, thanks that is really good tip, I'm sorry for leaving that one part out about her going for a week.
Also, what are some good ways to start a conversation?

Is it a good thing to bring back some fun memories about the time when i saw here for the last?

When you said, i'ts been a long time since i seen you, what have you been up to.

Like what exactly do you meen with that?