Outline of untitled story

Firstly, this is my first post on here, so if I've done anything unusual, my apologies. =]
I've been thinking about an idea for a story, it's in the very early stages, and I could do with a few ideas and comments on what I've got so far.

It's basically about a group of teens (16-18 ish) and the go through all these problems, like drugs, alcohol and sex, as well as friendship issues and other thing (that I have yet to think of!)

The Characters:
Mattea (Mattie/Matt) Adams [16]: She's that main character, bit crazy and spontaneous, is clever on paper, but often makes the wrong desicions in life.
Leila Adams [16]: She's Mattea's older twin, and the sub-main character. A little but like Mattie, spontaneous and clever, bit thinks about the situation more, and often makes the right desicion.
Ally Young [16]: Mattie's best friend, a lot like Leila, clever and pretty and doesn't get mixed with the wrong crowd, a very good girl.
Andrew Mason [15]: Mattie's long term crush, somewhat arrogant and mean, but very caring and considerate when he wants to be.
Chris Mason [22]: Andrew's older brother, a drug dealer. finished college and has a part time job at a supermarket, but makes money from dealing drugs.
Michael Carr [16]: Leila's best friend, somewhat annoys Mattie. A devout Christian, somewhat arrogant and tries to solve everyone's problems.
Felix Sanders [17]: Mattie's boyfriend (yes, she has a boyfriend and a long-term crush!) a sweet guy, caring clever and handsome. somewhat naive.
Jake Sanders [18]: Felix's older brother, a little less naive than Felix, and somewhat manipulative, but overall a decent guy.
Claire Davis [16]: Everyone's friend. an artist, a writer, a musician. the one everyone has no problem with, but sometimes left out of the "group" (she is also adopted, this is a factor for Mattie later)
Noelle Clarke [18] : Leila's crush. Lesbian. a nice sweet girl, brought up well, respectful and smart. sometimes confused, and makes situations more complicated because of this.

The plot was kinda complicated to do written out, so I put in a sort of time line,
(A note about college) This is a British story, and so the word "college" is not that same as the American "college". College in the UK is the American last two years of High School, it is optional, but a lot of people chose to attend, usually straight after they have finished secondary school when they are 16. It usually last for two years, one year for AS courses and the second year for A2 courses (usually) and then afterwards the go onto university, which is the same as the American college. Just a little piece of useful information for you there, and to avoid confusion ;)

July:
College induction day. Mattie, Leila, Ally and Felix will all be going to the same college in September. Mattie and Leila's older sister (Willow), who is in her final year at college, is walking with them. On the way home, some kids from the college are messing around with a gun, and Willow is killed.

August:
Claire wants to track down her parents, like most adopted kids do.

September :
First day of college
Leila gets invited out with new college friends > meets Noelle, crushed.
Felix's 18th birthday party, everyone gets drunk, then laughs about it in the morning.

October :
Mattie and Don have an argument about how she is playing with her life (alcohol and sex), annoys Mattie. Ally and Mattie start ignoring him, which in turn annoys Leila.
Don has a crush on Claire, who is being nice to him whilst Mattie and Ally are being mean, Claire doesn't fancy him back, so says she's a lesbian to avoid turning him down, Don isn't fooled, but doesn't say so.
Claire finds her parents, but they do not want to meet her, and she is somewhat saddened by this news.

November :
Chris gives Mattie drugs, LSD, and Leila flips out
Leila really fancies Noelle now, Donovan disapproves which annoys Leila, and Mattie's reaction of "aww bless, your first girl crush" annoys her too.

December :
Mattie needs drugs, but has no money, Chris offers her them for sex, which Mattie does, Ally finds out and is really mad at Chris as well as Mattie, and tries to get her off drugs, with little success
Christmas party! everyone gets really drunk. Mattie has sex with Jake, thinking it's Felix. afterwards, realizes it isn't Felix but ends the relationship with Felix before he finds out.

January :
Mattie is pregnant, but who is the father!?!
Mattie decides to keep the baby, as killing things is wrong.
Mattie immediately forces herself off of the drugs
Mattie decides to get a paternity test
Claire and Andrew get together.
Claire's biological parents change their mind about seeing her, and arrange a time and place to meet, but then cancel it.

February :
Mattie is struggling and feels that she is going to fail herself, her baby and everyone else she cares about. She wants to give the baby to adoption, but knowing what Claire has gone through with being adopted she doesn't what that for her baby either and goes against her decision, and goes for an abortion, but Felix stops her, and says he'll be there for the baby. Mattie tells him he isn't the father, Chris is, and Felix says it doesn't matter.

March :
Leila moves away to go to an acting opportunity, Mattie doesn't want her to leave and Leila didn't think Mattie cared that much.
Mattie decides to become a Buddhist, and Claire and Ally become Buddhists too to help her.
Micheal decides to give his opinion about Mattie's decision to have a baby and change her religion, which makes him really unpopular with all of the characters

April :
Chris gets Andrew to pick up drugs from his dealers whilst he "deals" with his ex and son.
Claire protests, Andrew forces her with her to make sure she won't tell. Whilst getting the drugs, the man Andrew is supposed to be getting them from acts up, and Claire steps in to break up the fight that has broken out between Andrew and the drug guy, but it results in her getting stabbed by the drug guy.
Claire is taken to hospital but has not suffered significant damage.
Claire's biological mother shows up, and says that she wanted to meet her daughter, but her husband (not Claire's dad) did not. Claire asks who her father is, and her mother says "the one who adopted you"

May :
Claire is struggling to deal with life, and wants revenge on not Andrew, but Chris. She starts to do little things, like move where he's left things, and using his phone to send messages to make him angry and slightly crazy. She then changes his drugs for something more concentrate, and he overdoses.
Chris is taken to hospital and dies.

June :
Mattie's baby is born premature @ about 24 weeks.
[insert extreme emotions here]
Upon hearing this, Leila comes home immediately.
unfortunately the baby dies :(
Baby's funeral


This is an edit, the first version started in September with an incredibly dull intro, and also left the last few months eventless. I've added more death and problems in this update though >:) greatly appreciated, also comments on what I've already thought of, if it's good or if it needs improving, or if it's absolutely terrible and should be compeltely moved from the plan.
Now .. I just need to get the energy to start writing the damn thing :)