After 15 years living in the city of Manehattan, 8 orphaned siblings take a risk that may turn their whole lives upside down! They move to Ponyville, where everything is much more friendly and peaceful, unlike the busy streets that they used to live in. Join these siblings; Absolute Zero, Fiery Rose, Arctic Lime, Heat Wave, Winter Sky, Spring Frost, Lemon Glacier and Sizzling Sunset on their breath-taking journey from the busy streets of Manehattan to the cheerful grounds of Ponyville!
Chapters (15)
Your story was actually really good for being OC-based. Only a few problems;
-the random CAPITALIZED words could have the same effect with italics.
-There's a lot of characters, but there's no need to describe what they look like every time they're introduced.
Maybe {"And that's [name], [name], and [name]." Twilight said, pointing.} would work better.
-There really haven't been any comments on them other than their 'extreme' coats.
-Some of the Mane Six are acting a little OOC.
-You mentioned the foals at the orphanage calling them 'the Extremes' before they reached Ponyville.
Also, there was a glimpse into something odd when the unicorns combined their magic in the library; Twilight mentions that they have a stronger bond than Applejack and her family, and then the subject is promptly dropped. You had a great chance there to expand, and left it.
But this is your first fic - and judging by your username, your closest OC's - so you did do a pretty good job overall! Thumbs up from me!
I agree with the last person. Pinkie talking does not always have to be capitalized, the mane six in this story just don't seem like the real mane six. There are too many characters. I cant remember any of their names or what they look like. It is way too confusing. This could be a lot better if you put more effort into it.
1428689 Thanks for the feedback! Sorry, I'm only 11, it's hard for me to write a proper story!
But thank you anyway for the feedback, I'll accept any complaints, and i'll try to fix the mistakes as soon as possible! 
I want MOAR!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1
How old are the siblings?
Its pegasi. Also the story feels rushed. Good gramar though