Talking to her again: what to say?

Hello everybody! Since I broke up with my girlfriend, I discovered a whole new world. She was my first girlfriend - in 17 years! - and before dating her I had been wondering if the world hated me. But, as I know since the first kiss, it didn't. So, now that I'm technically "free" (though I preferred dating a girl and being not!), I'm really "looking around myself" (this is an Italian figure of speech... do you say that in English?) and I see many, many girls that I might like, provided that I can somehow get to know them better.
First and foremost, there is this girl from my own village of 800 people. She was my first love: I fell in love with her back in 8th class, but since the following year we went to different high schools I've never talked to her again. Until Sunday.
After having dreamed about her for so long (even while I was dating my girlfriend), I've finally had the courage to try and talk to her. Actually, in the beginning there was no real "talking": I found her profile on Ask.fm, and used it to tell her how beautiful she was. She thanked me and asked me who I was, so I started being as mysterious as I could. I was able to get her friendship from a false profile on Facebook, but she didn't trust it, therefore I had to tell her who I was. We've talked for some 15 minutes (it was Monday already), but then I had to go to the doctor's for a document and stop the conversation.
Since then I haven't started any other conversation. It's been 4 years since we last met physically, and I don't know what kind of topic I could use. I don't really know what people she hangs out with, either - 4 years are a long time! But I've never forgotten her.
OK, so, the main reason for being here is asking: if a boy you haven't met in 4 years and blah blah blah started to talk to you, what topic would he have to pick to be [as] sure [as possible] to get into a long conversation with you?

PS - I'm sorry if my English isn't exactly excellent. I'm Italian! Any correction will be appreciated :)

Well, first of all, your English is fabulous! And I love your country. Been there many times.
To the isue: I wonder how it would be for you to meet face to face and, "catch up on old times." That means, review with each other what's happened since you parted. You have four years to catch up on. Good luck! Let us know! Ann

Well, thank you! It will be even better in the future since I've just learned the expression "to catch up on" :)
The problem is that we've talked just a few times, at present I still don't know how on Earth I fell in love with her. All I know is that I dreamed about her once: in this dream, the TV news talked about a family that had mysteriously disappeared from Amazonia. Then, the dream fast-forwarded to a couple of days later, when all of her family BUT HER had been found dead. I swear I hadn't smoked anything the evening before! However, I suddenly realized how much I cared about her, and it was not difficult to find out that what I felt for her was love.
I've been dreaming about her many times in these four years, but, as I said, I haven't still found out what made me actually fell in love with her. I guess it was her smile. She made my days better in the period that followed my best friend's death in an accident, and I'll never forget about that. However, we talked two, three times. We don't know each other that well. We could catch up on old times, as you say, but I fear it would be kind of awkward. Do you have any other suggestion?

Just say....it's been 4 years! so what have you been doing with yourself? going to college? working? what do you do for fun? Want to hang out sometime?

What sports do you like? Take her to a game. Have a picnic lunch somewhere. Go have ice cream. A movie....a concert......there are just millions of things to do in Italia. Why would catching up on what has been happening in each of your lives be awkward? Ann

You are probably right, it's just me. Unfortunately I don't like sports (besides Formula 1, but you know, I don't have the money to take her to Monte-Carlo tomorrow)... and, è vero, ci sono milioni di cose da fare in Italia, but not in my village XD I'll just catch up on old times and see what happens.
Grazie mille!

First of all you should ask her how is she. Is everything still okay, is she finish her college life? Or ask her to hung out with you sometimes.