Confused about this girl

[hhhhhhhh123]

Hi so bit of a long story

Around six months ago I moved from my old university to my new one. Immediately on my course I met a girl who was from the same city I was. I developed a crush on her quite quikly because she was pretty and a fun person to be around. In our first few meetings (in the train station or before/after lessons) she was always smilling and laughing when i was with her.

Eventually we both ended up in separate friendship groups and ended up not talking for quite a while. I wanted to talk to her but some of her friends dont't like me so i stayed clear of them. The other day our classes got merged because of staff shortage and she was on her own (because her friends wern't in that class) so I thought heres my chance. I went in and sat next to her, I tried talking to her but all I got were one word answers, eventually the silence became awkwardness and she ended up on her phone for the remainder of time. I told my friend the whole story and he said she probably felt shy/nerveous around you, this made sense cause she does have a bit of a shy/timed personality. I've caught her the odd time staring at me across the room in lectures and stuff but never really figuered out what this really meant. I've also noted that when shes around other guys shes loud and laughing but when i'm with her she goes all quit and tries her best to limit conversation. I really dont thing I have an off putting personality or anything because most of the time I can make friends really easily, but when i try to make her "talk" she doesn't reciprocate.

So why did she go from happy/laughing/smiling to reserved and quit?

[Hooo!]

because some of her friends who do not like you talked shit about you behind her back?
just a likely scenario

if she does this everytime you could go on full blast and ask her about it and that she should decide for herself (for example on a hot mug of coffee) wether you are whatever anyone said you are or no.

or you could just take the hint and drop it.