Is it harder to socialize with girls in University who aren't classmates?

I am a 23 year old guy living in Bangalore in India but born in Siliguri in West Bengal in India who has been very shy near girls in person and even avoided talking to them as I got severely bullied in high school which resulted in very low self-esteem. Currently I am studying MBA and only recently I am talking with girls in my University but don't have a social circle as i have less friends. I just entered 2nd year of my MBA which is my final year and I will graduate next year and I was still a bit shy near girls in my 1st year in MBA so even though I had a crush here and there, nothing much developed.

But the girls nowadays I am talking to aren't my classmates. They are either in the same year as me but different classrooms or my juniors in 1st year of MBA so anyways most of them are within 22-25 age range. But due to my lack of female interactions for years, I am unable to keep the conversations going on and most of my conversations with girls have been Hi and how are you or something about University related and the conversation ends with saying each other bye as I myself get nervous or she soon gets accompanied by her friend. Many of them already have their friends circle and I feel that I won't fit in or have a deeper connection with them as I am not their classmates and they already have friends. Today I did initiate conversation with one girl who was with 2 of her female friends. It was brief too only hi and how are you but her friends didn't expect it probably and were surprised and laughing with a surprised face as they didn't know me. I did talk with the girl once or twice previous but there was a gap of almost 2 weeks since our last conversation.

Only with one girl things aren't as hard as she is an introvert too and she is 22 and soft spoken and we had in person conversations for 10-11 days. But few days ago, when I was I my hometown, she suddenly unfollowed me on Instagram for no reason right after viewing my stories even though we had positive in person conversations and the previous 5-6 days were an emotional roller coaster for me due to the confusion and uncertainty about the situation but today we finally met in person and she again talked normally and smiled too when I said her Hi so I wonder why she unfollowed me and I didn't ask her yet about it. But with the other girls, I am only talking briefly as they are mostly with friends.