Now to explain myself better, when typing on PC keyboard.
Its not that much has changed, this was a typical pattern with her, I'll give you an example:
we spend great intimate time, usually one weekend day with great sex, and then the the following 2-3 days after, I feel like she needs other distractions from me, even though she contacts me just for the sake of small talk. I can now already feel her emotional states, and detect monthly phases(I don't mean just menstruation/ovulation

) - in other words - the patterns.
Two times I have called her out on her clumsy behaviours, and she got silently mad because I was mad. Then later on she admitted her overreaction. See the way she is functioning?
I know you can't be emotionally crazy for relationship all the time, I have my own hobbies and distractions of course, but I still think all my girls have always been more unstable/inconsistent than myself after infatuation stage. And I learned to not show beta behaviour in this relationship, even when I'm insecure or actually in beta mood, I've hold myself not to show it. But when in relatively established RS which is 6+ months long, just here and then insecurity will pop out. I also have to deal with her slutty experience in past, presented in other topics, and take the risk to be her first bf.
The thing is, I have my own friendships, and much more concrete hobbies than she does, but these three days when we only contact on chat - my friends were busy, and I couldn't hold within 4 walls 24h, but she didn't even ask me to hang out, about what I'm up to, whereabouts, so I've gone to walk alone, while she is once again hanging with her girl friends(I certainly hope so, haven't caught her with men really). Maybe it's a mistake, but once I was stoned and had a bad day, I told her she doesn't give a crap about me. Then she acted stunned and said she thought "we were already having that high level of communication, understanding and trust". And she thought that I was making uncalled drama. However, the effect being - afterwards she first time started to invite me to hang with her friends outside, and generally was more conscious. Nevertheless, it lasted shortly. Now again its like: "I'm going now

" to end our conversation, not mentioning our time priority, like she takes it for granted. She knows I'm having an exams, but I don't think thats the reason.
Maybe we talk too much online, but it was her initiating always. Since she's a summer type, and has the free time, while I get to work on college exams, now I have to handle her going out like crazy. She's objectively good looking, and gets hit on often.
Monday she called me to hang out together, next day she was gone to exam to another city, had free time fun afterwards all day, the next one just contacted me on chat, and today the same story. If she continues to act like this in matter of days, would you even ask her to come along on weekend when its time for two of you, or would you start freezing her out?
And when I do show just small weakness by being suspicious or openly calling her out, I get the feeling that she'll pull the shit tests in return at one point. And I don't want to be hard-tested all the time, if this lasted certain amount of time already. She shows the want to be serious about this, but still acts idiotic at times.
Now what about space, going out separately, having this amount of individual time, is it natural or a problem?
Somehow, my relationships always start to fall apart during summer, when they start to hang out so much.
Since now its obvious that I am not well built and I'm skinny, could it be that they loose attraction, though I techically function well in psychological/PUA sense? I plan to continue working out and stop smoking soon, but until results the relationship may quickly break if this is the reason
Could someone discuss this question of line between acting like you're single and normally having life outside of relationship?
Is it really the problem that she is 18yr old, and I am 24?
I should cut the following suggestions immediately:
"see other girls" - No.
"Start not giving a shit" - No, if she doesn't change drastically, then I won't as well, I-am-who-I-am, and don't consider myself needy, but I won't forcefully change my deep inner psyche to adapt.
"I'm over-analyzing". I know, but life is hard enough without relationships, I analyze when I'm confused or afraid to waste the time on something.
I'm just trying to understand dynamics. Conclusion is, she always made my insecurities look misplaced, thus later on I would usually see I overreacted, but sometimes she amplifies them perhaps unconscously.
I can't be the one to speak: "I think we are not spending enough time together and you don't seem to want for some reason". So what is the right thing to do

Leave it where it is?
Many details here.