I'm (17M) the classic "quiet guy" in class. Did I completely misread my classmate's (17F) behavior, or was she actually flirting?

Hello, I'm 17 years old Italian, I'm really introverted, highly self-controlled and closed socially, so basically I'm the classic quiet kid in school. I'm really perplexed on the behavior towards me of one girl that is in my class and I can't understand if it's interest or her just being friendly. It happened various times during the school year that I'd notice her doing strange things towards me, mainly in the end of the school year, so I'm going to just objectively say all the things she did towords me that were interesting to me.

My suspects started when one day me and my class were in the gym. As always my teacher and the class pushed me to play with them volleyball. Being how I am, I hate sports too much centered on teams and having to move a lot really close to other people, plus I suck at volleyball. Anyways they put me in a team with the girl I was talking about, at a certain point I manage to score a point and my team cheers me, and for some reason she cheers me by blowing me a kiss from the distance. I was too embarrassed for that so i just kinda ingnored her. I've never seen her doing stuff like that to any other classmate, but I don't really know.

Another thing that she did during the year is that she consistently chose to stand or walk way too close too me, entering my personal space during the chemistry lab while there was plenty of space in the room. This may mean nothing so i wouldn't really count it as relevant.

In June we spent like a week together alone in class because everyone else was already done for the year (in Italy, if you have enough presences in class and good enough grades, you don't have to attend the very last days of school) and we had too many absences and had to do some extra exams. In that week I don't know what happened to me or what she did to me but I could talk and joke with her like nothing. We passed good times, laughing a lot and helping each other trough these days and she was really expansive and kind, which was probably the reason I maneged to relax and be myself with her. One of the best days was when I was helping her study english in class for an oral exam she had a few hours later, we laughed so much and in the end she even got a good grade on the exam. While I was helping her a teacher saw how we were interacting to each other and told us to sit together in class again the next year, and after she turned to the other side for a second the teacher looked at me and winked at me...

In the last day of school happened a lot, it was always just the two of us in class. The first thing that happened was the day before, she messaged me offering me some help for a project I had to develop as an assignment for the school telling me "Today if you have time write that thing (the assignment), if you want I'll send you mine so you understand how to structure it. So tomorrow in class we'll make it prettier on the iPad and then upload it" (obviously I'm translating what she said from italian). That same evening for some reason I tried to do it by my self at home, but the day after in class, which was the last day of school, she decided to make it prettier anyways even if I had already finished the thing, while she was changing stuff on my assignment she even changed mind more times on what she was doing changing multiple times font, color, size of the text and background.

Always the same day, after we finished the last touches on my assignment, she asked me if I wanted to play a quiz on her IPad and so we did. While we where playing she even messed up with me faking to not know basic questions and seeing my reaction and laughing telling me that she was joking. Later, after we finished playing, she returned from the restroom and asked me a question saying "would you do another week like this?" and, stupid me, I respondend "no, even if I still have to come to school this summer because I have to make up for some bad grades" and she said "at least maybe we'll do it together", and I reassured her that she was not going to be low on any grade.

Always in the last day of school she did an interesting goodbye before we both parted for our homes. She leaned her cheek to me for one of those italian greetings, the kiss cheek to cheek, which really embarrassed me because it isn't common at our age or at least I never greeted anyone my age like that, and neither did she with other classmates. In the end while I was walking to the bus stop she passed by me on the road with her scooter honking to me.

So, this is everything that happened with her, I still am not convinced in any way if she was interested or was flirting somehow but people keep telling me that she was and my mind is just in denial. I would like to know the opinion of a more international audience that's why I'm asking here. Sorry if there is bad grammar here and there or i didn't express what I was trying to say in the best way but, as I said, I'm italian and english is not my first language. Oh, and sorry for making this soo long and thanks to who as the patience of reading all of this.