Hey Joyce, if you look anything like your avatar, you are pretty, and the girls may be jealous of you!!
I remember every time someone new came to school they became center of attention and some boys/girls fell in love with them etc.
It is quite possible that Shelly is now afraid to not be the 'top star' in the class/at school!! Maybe she's even afraid her boyfriend or the guy she likes might like you!! (Maybe that's even true!!) Soo... she does everything she can to prevent it from happening-??
Look around what clothes other girls wear. Are your clothes better looking or sexier and more revealing? That may provoke them a bit..
I don't suggest to change your style to adapt to other people just because of some mean girls, but if you're young it's better to not wear too sexy/revealing dresses/clothes anyway... You might want to let your personality shine through, not everyone to be just distracted by your clothing or any skin/cleavage.. (This is just hypothetical, no idea what you wear, I observed some girls in high schools do wear very revealing clothes, which do seem inappropriate for their age..)
People may get weird ideas about girls just because they want to be fashionable!! (And guys, or old men - or other girls - might get the impression she's 'easy'... even if it's totally not true!!)
Soo.. if they wear sweaters and don't show bellybuttons, it may be better you do sorta similar..
If you make your own clothes/bags/etc - maybe they're jealous you have 'boutique'/expensive-looking stuff? (If someone admires it and you like making it, you could even offer to make one for them, if they're nice to you etc.)
Join a club or special interest group. Ideally something that really interests you, and with some cool and some not-too-cool people, or at least people who are nice and friendly.. Is there an artsy/crafty or eco club at your school? If not, could one be started?
How did you find people at the old school/s?
Not-too-cool people can be easier to talk with, they may be happy to find a friend, though if you're goodlooking they may be intimidated and want you to start conversations first, smile at them, say hello...
I was surprised that a classmate was sorta insulted when I didn't say hi to her specifically, I said hi to people around her...
Look for people you like and feel drawn to, find a reason to talk to them - eg 'Wow, I like your ___(hair/dress/bracelet/bag/gizmo)____, where did you get it?' Ideally only genuine praise for things you *really* like!!
Or even if they wrote an essay/poem or what they said in discussion in class, say something, 'Great essay..' or even describe what you liked about it..
Find some trusted adults too - maybe the librarian or cooks or other teacher/s of your favorite subjects, or where you're good at, maybe even a janitor (if friendly looking and married father, respectful/respected..) Ideally older women though, probably... So they can't accuse you of 'seducing men' etc. Or new youthful sassy 'cool' teachers, who can firmly stand their ground with the girls and don't have problems with them in class.. Ideally someone the girls fear a bit...
Volunteer if you can, get teachers' good opinion... (But not too much, you want to walk the fine line of getting along well with teachers and kids, don't be 'teacher's pet' but it can be also good to have two or three teachers at least on your side.. If you have good grades that can be easier..)
I'd also report the girls I guess, have yourself photographed with what they wrote and maybe threaten to sue/pursue action? Are they rich? Could you actually sue them or something, for attack? (Might wanna check the laws with a lawyer??) Can you press record on your cell phone (or small hidden mp3 recorder if they ever attack you again, and record what they say?)
A friend of mine who was a waitress said to a guy who threatened her: 'I hope your father is very rich.' He was confused, 'Why?' 'Because I'll sue you for every penny...'(I don't remember the exact words, but it worked, he backed off..) Even if they're not rich, some laws say they can 'work it off' with their future paychecks that go to damages.. Again, check what it's like where you live, there may be free legal help available too.. or there may be info online..
She also had telephone number of police in her cell-phone, so she could dial it quickly, if needed.. Maybe there's a waitress or bouncer or someone knowledgeable locally who could give you some more tips?
As a waitress, she also acquired a mean frown that scares kids too!! (very helpful!!)
Sometimes it might help if a parent or older relative or acquaintance/friend, someone 'strong and mean' comes to school and yells at the person/s, or even does this by phone, not sure how it is with teenage girls though.. Maybe there's some info online for dealing with girl bullying specifically, google for it..
Otherwise, ignoring can work too, yup... even very well sometimes..
You can pretend to be busy with other stuff etc, walk briskly and quickly, like you're confident and heading somewhere and in a hurry..
Does your school have an anti-bullying or mediation program? Can you go to a counsellor or such? I expect parents or teachers wouldn't think you wrote that on your forehead by yourself??
Anyway, good luck hun!! I hope you find good friends here too!!