AITAH for going back?

I (19M) have this "friend" (19F). Me and my "Friend" J have been friends since we were 13 or so. We became friends via a mutual friends but our families are distant friends. In addition to that, my sister and J's sister is also friends. Me and J had been platonic since we got to know each other. No feelings. Only friendship. We used to talk daily for a few years, but never met up in real life. When me and J were 16, we got into an argument and we stopped talking. A year later we found out via our sisters that it was a miscommunication so I reached out and we were friends again. We still did not see each other in real life. We had a little distance after that argument even though we were friends again. Last year when we were 18 and 17, we decided to hang out and it was quite fun, so we started hang out a little frequently. I realised that I liked her as more than just a friend so I admitted my feelings, but she did not feel the same, so we took a break from talking to each other.

After a few months I saw her walk past me and my friend in school. (Yes we went to same high school). I approached her to ask if she could vote for me, as I was a candidate for school student council president. She said of course and later messaged me on snapchat. We started talking again, and this time she started flirting back and we began hanging out again. She surprised me with food she had made for me, initiated hangouts and showed me where she had the birthday gift I bought her and said I am the only guy she has ever hung out because I was "worth hanging out with" and mentioned subtly how she liked my personality and got upset when I could not see her dance performance. Am I delusional or did she give me romantic signals? The thing is that J had a lot on her plate. She had another big dance project coming up and she had to keep her grades up in order to get into medical study, so her making time for other activities meant a lot for her.

Just as things started escalating, she mentioned this other girl in our grade which was a friend of us. She wanted to set me up with her. I said I did not want to and hinted that I liked someone else (J). Then I the worse got of me and I gave in eventually to see if she would get jealous. She did not seem very jealous. She set us up, and me and this girl (N), went out on a date and somehow ended together. When me and N got together, J started getting colder and distant and even stopped talking to N unless it was important. N and J were relatively good friends before until me and N got together. After almost a year, me and N broke up. Now J lives in another city, while I am taking gap year. Next year I am moving to the same city as J studies in as the course I am going to apply for is only in that city. Now I regret that I went out with N.

The thing is that me and J are from the same country and hence share same culture. In our culture love is very slow . She have not had any partners before. Neither did I, before N. By slow, I mean as you start of as friends and hang out many times before it progresses into something more. And that is where I felt it was heading, but now I feel stupid for letting my ego come between me and J.

A few days back it was J's birthday so I congratulated her and she gave me a warm response back. Could it be maybe because J found out I am single? Am I delusional or did J really start to like me more than as a friend? Is it too late to go back to her? I saw J post a picture on her story of herself and it hit me, how much I liked her. Now I am thinking about her alot. AITAH for wanting to go back to try pursuing her again? And AITAH if I pursuit her?