SUBREDDIT: r/relationships
TITLE: Me [21 M] with my girlfriend [19 F]. Different expectations? Lack of communication?
POST: We used to date some time ago. She broke up with me 4 months ago and 3 weeks ago we got back together. I guees? We're dating, nothing serious though... we don't make plans together, we don't spend a lot of time together, we don't text very often but when we meet it's always awesome.

Anyway, beside the lack of texting and meeting twice a week we also didn't have sex yet. When we first started dating we were both Vs. After the break up I decided to start hitting on girls, I got laid, couple times. Dunno about her. She likes to takes things slow. We didn't talk about that yet.

I don't feel any pressure on having sex, right now, here, go ! No, don't get me wrong. I liked it and I'd like to have sex with her but I don't want to rush things.

* Should I talk to her about that matter? 

* If so, when would be the right time? Last time I tried to make a move she wasn't up for that. Too early I guess.

* How to make things a little more serious? I'm a total newb in relationships. How to show her I want something more?
TL;DR: 
Got back with ex and we have no sex. Wait or come up with the topic? Plus, how do I make things a little more serious?