Is it correct to write, 'My writing is still immature, but I would appreciate it very much if the admissions office takes a look at it?'
It would be really great if someone could help me as fast as possible.
"Immature" is not generally a word I associate with writing. I would perhaps say "My writing still needs some improvement but I would appreciate it if the admissions office would consider it".
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.