I like this - or is like really the right word? Writing it in the form of letters is an interesting way to go, and the first line was great. It really drew me in and made me want to read more. This story really emphasises how awful it is that this kind of pressure is forced about girls as young as thirteen entering the fashion industry, and makes readers feel passionate in their defence. The second chapter was definitely a little more reflective - it's interesting how Jane almost blames Alice for dying. In these situations it's common for friends and family of the sufferer to feel angry, as it seems like something they can control. Jane's overall mentality and thought processes seem pretty accurate - it's so twisted that she feels she has to lose weight for Alice's sake, but can't see that she'll just end up the same way, killing herself the same way Alice did.
There were definitely a few scattered typos and grammar mistakes, but those can be edited out with a careful read-over. Overall, nice job and I look forward to reading your next update! xx