What to do?

Alright so I'm 18 and in a situation here. There are two girls in my class, lets call them A and B. Both A and B are interested in me. B is really like after me yk, she goes around college just looking for me, tries to approach me and regularly sends off random compliments and is really frank with me. However I have shown her no interest, since im not into her. We're not really close friends either, she tries to become close with me but I always resist. On the other hand me and A developed a good friendship. We talk often, and somewhere in between I had developed feelings for her. Here I'd like to make the situation clear, both A and myself are conservative and not really extroverts. Although I have a charming personality, im just not good in conversations except for my close friends circle. I have a really close knit all boys circle, while she has a really close all girls circle and she has no other male friend apart from me. Hence, the conservative part. Another point is that I dont know any of her friends and neither do her friends know anything about me, or so I thought. It was her birthday the next day and I had no idea about it. Later at night, i was called by an unknown number (calling eachother from where where im from is not usual especially between opposite genders who do not know much about each other), turns out it was one of A's friends. She called me to invite to a surprise party they had planned for A. Later, i wondered how the hell did she find my number, how does she know me ? How did she know I was friends with A when our friendship was super lowkey. So i guessed it out that A must have mentioned me among her friends, to which my heart was fluttering. Anyhow, i did go to her brithday and here i noticed stuff like her friends acting super cheeky and A herself being really open around me. I knew for certain that she was interested in me since I overheard her friends teasing her about me..After that i actually spent the entire day with her. Later that day she said that she really enjoyed spending time with me and appreciated me attending her birthday. Alright now I was dead sure she was interested in me from all the signs i observed aprt form what ive mentioned. It was a great feeling, imagine my crush also crushing on me aayyyy. 😂, Anyhow, later she messaged me, "what are your plans for the weekend", here i was just too shocked, like she was making moves here. Anyhow I replied, that i was free and did she have something in mind etc. After some time she replied with a medium sized paragraph, which began with "Yes so i was thinking maybe....." I was reading it when she deleted the message super quick. And replied with nothing just asking. I was kinda disappointed but realized maybe she wasnt ready or didn't have the courage or maybe just wanted me to take the initiative yk. After that, i mean we've been talking regularly but like none of us is making moves. Recently, i noticed that she wasn't replying as fast to my messages and stuff. But ig maybe thats because we have exams n stuff this week. Cant really say much. Im not good at talking to girls since i dont have much experience in this department. I think maybe i should confess to her, but fear a no as the answer. Im preparing myslef however im stuck. The situation is that in a month we move our separate ways towards uni so this is really the only time i have with her does she like me or no. Really mixed signals, recently i feel disconnected with her, again I'm guessing due to exams. What shoudl I do?