Tl;dr: Girl I recently met shows many IOI signs, but at the same time only initiates conversation when it's about school. I just want to start out by I'm a fairly confident guy, I know how to talk to women, I know how to flirt BUT I've never taken it to the "next step" with any girl whatsoever. (I'm 18 soon to be turning 19).

This post is about a girl in my university that I recently got to know. The first day of college I sat beside her and started the conversation from there. On the same day I asked her for her Facebook and added her. Fast forward I wrote to her on Facebook, a really short conversation really (wanted to keep it as short as possible) just to ask her a couple of questions about the university.
The next day I was sitting beside her and then this girl from class comes up to me and asks me some questions about where I come from, and that she is curious because I have "really blue eyes". From my perspective that was a good thing because it did DHV and it was a good time when she approached me.

Classes pass by and we talk more often, I kino, and she responds pretty positively and starts touching me whenever I tease her. Let me add in that we are learning Python (Programming language) that I'm fairly decent at because I work with it on personal projects, and she knows that I'm good at it. The system in the university is that you can work in groups or solo, and a couple days ago she messaged me on Facebook saying (Sorry for awkward wording, translating from my language): "I have reserved you just so you know" to which I responded "Group partner?" and she said "Yeah haha" etc etc and as always I tried to keep it short and didn't even respond to her last message but basically I agreed.

Now this girl is touching me more, last class she sat next to me and we talked and she asked me to stay with her after university to explain to her a couple of things. (I already had things to work with so I told her that I can help her as I work with my own stuff). The same day we went to the cafeteria at school and she sneakingly paid for what I got without letting me do anything about it, when I tried to pay instead she said "Hey it's only a drink, you pay next time" with a smile. Fast forward to yesterday, she text me at 1 a.m telling me that she needs help with Python, I found it really weird that she would text me SO late at night but I tried to explain a little (with teasing her) but realized she still didn't understand and I didn't really wanna bother explaining via text so I told her to call me. The conversation went:
Me: "Call me I'll explain -number-
Her: "I can't, I'm at -hometown- and my parents are sleeping"
Me: "Are you gonna scream at me?" <- Joke cause I teased her earlier
Her: "Haha no but the walls are made out of trees" <- Lol wtf?
Her: "But I will call you tomorrow and you can explain"
Me: "Haha walls made of trees"
Me: "Yalla(aka alright?) call tomorrow"

She didn't respond, and I never expected her to call today (Which she didn't) but to my real question.. is there any interest or does she just want to get free help from me? She is giving me those strong IOIs but at the same time it's often school related. Am I over-analyzing? Is it because school is our only mutual subject to discuss SPAM? or is she just using me for free help?

I have no idea guys, and I would really appreciate tips in how I could escalate FURTHER with her, like how to ask her or whatever. Thanks for reading!

Sounds like she's interested. Use studying as an excuse to isolate her. Then escalate. Quickly before you lose her.

Her interest seems centered around her academic interests to me... Don't really know what you're considering IOIs, but I don't see a whole lot here to consider her to be 'interested'...

With that said - why wouldn't you just escalate and find out? Would have even been faster than posting thing thread, and you'd have your answer

I disagree with Charles. When I was in college girls who were interested would use studying as an indirect approach like some guys here use opinion openers. Either way, the only way to find out is to escalate.