Marrying one's student
Q: I am a Muslim and 29 years old. I was an engineering student and during my bachelors education I used to teach Science Subjects to Intermediate co-education classes (11th and 12th Grades) in an Academy to meet my expenses as my father was suffering from financial crises. I used to control myself from developing feelings for the opposite gender and I succeeded nonetheless.
After 4 years of teaching, when I graduated from University, I found a better job and went outstation and I have been currently serving as a Senior Officer for 6 years.
When I got my job, my parents started searching for marriage proposals for me but they could not find a good proposal for 2.5 years. It has been 6 years since I left teaching.
The issue is that 2 years ago, I along with my class fellows had a get together in the University, and after having the meet up, when I was going back home, I saw one of my past female students (She was the sister of my my class fellow and I knew her even before teaching) in the University Library coming in front of me after so many years and her habit of keeping her gaze low and noble character forced me to develop feelings for her and I started to think about her as my wife.
After thorough thinking, I then sent my proposal through my family to her family and her family accepted my proposal whole heartedly because they already knew me.
My Question is that Is it allowed in Islam for me to marry her as she was one of my old students although at the time of teaching I did not have feelings for her in my heart and I am not teaching anymore?