This large chunk of text is from a book that I'm writing, I'm looking for feedback&constructive criticism.




"With an intake of air Nat threw the door open...
In those three seconds the very next sound he heard was the sound of a wooden drawer being yanked open loudly and hastily. The door was open and he stepped into the classroom to see a Nigerian man with a look of sheer terror, leaning down to snatch up something from his open desk drawer. With an exhasparated and heavy sigh of relief, the man got up, revealing himself to be not much taller than Merrietty.
"Woohh...sorry son," he rolled the drawer shut, "I was simply startled by your...face." he finished, trying but failing to hold back his dry cackling.
Nat glared at him, arms crossed over chest; he wasn't amused. Mr. Arthur didn't get much pity from the rest of the class.
"Ahh...sorry, again," said Mr. Arthur, still chuckling, "Are you lost? What do you need?"
Nat stated impatiently, "Merrietty, Nat, transfer student."
He nervously chuckled with less enthusiasm, coughing into his hand afterwards, "Well did you have any trouble finding your way here?" not really wanting to know the answer to that question.
"I would have, had I not been shown the way by Ms. Corretta."
Mr. Arthur's expression deadened, and his eyes opened wide. "Right...good." he mumbled before seating himself back at his desk, squaring off several unruly stacks of papers, "Right...well, pull up a seat next to Bart and Reilly, you're with them from now on, seeing as they weren't unlike you until recently."
Upon hearing this, two boys in the back row traded glances, one groaning with irritation and the other rolling his eyes; the second pulled out the chair of the neighboring desk, then signaled for him to come over. 
A girl in a green shirt smirked and then whistled at him playfully, her friends giggling as he walked by. He felt like everyone was eyeing him suspiciously...
He sat down and his new deskmate greeted him, leaning on his elbows and giving Nat a cheerful yet forced looking smile as if he was trying to appear much more interested than he actually was.
"Kay," he began, "Well he's not Bart and I'm not Reilly;" he easily spotted Nat's look of confusion, "Think the other way around." Bart said with a single twirl of his finger, now smiling a tad more honestly.
"Kay," replied Nat, mockingly, "Well my name's Nat, in case you weren't listening..."
"Well ain't you just adorable?" Reilly teased.
Bart shot Reilly a look that said to cut it out, then turned back to Nat, "So? What brings you to a place like New Ana Leya?" "I can't go into that right now...." Nat said, trying hard to not look Bart directly in the eyes.
"Oh...perhaps some other time then."
"You don't talk much, do you?" Reilly stated, already growing impatient with his new peer.
"...You don't think you'd learn to hold your tongue after destroying someone's life with it?" Nat shot back, impatient with his new peer's impatience. 
"..."
"..."
"Alright Merrietty, we get it, you are the master of the 'tongue'..." cracked Reilly, before Bart burst into relentless laughter. Reilly merely looked disappointedly at Merrietty, completely unamused with his quips.
"You need to come on; humor me already." he spoke, breaking Nat's concentrated demeanor. Nat looked hopelessly down at his hands as they lied still on his cold metal desk-top.
   "Hey.." he heard from his left side, "You need not worry.. you're safe here." the words flowing past Bart's bright smile, and his eyes too smiling into Nat's. He let out a sigh, begrudgingly, and from that point onward everything sped up, as if life had gone into fast-forward. From the dreary atmosphere to the aching voices of student's laughter to the inspired scribblings of Mr. Arthur flooding the whiteboard with information on the false unification of the planet to the flash of sunlight from the sunset peering through the windows to the exhaustingly dreamy sounds of the world winding down and giving out to the pressures of gravity, footsteps papers flying through the air and the sweet smell of perfume... and it was just as this was that Nat's eyelids fell down, heavy, his young mind parting with the waking day, in sleep..."

Well I personally have to admit I haven't read a book in a while to be the best judge on how things should be written. But I think its really cool that you are actually writing one. It can be a big challenge, so really hope that goes well with you. Don't give up. It's very likely you'll hit hard spots not knowing the words to say, but keep at it. Would be really cool if you had your own book published. From what you had for a preview I was able to follow it, so you do have something here. Keep working on it, and of course have fun with it

Aww well thank you!  ..tbh I was really afraid of the response being negative.
And no worries, believe me, I don't have the patience to read most books, just to write them! I read a lot last year, buuut that's about it.

That's fine. Writing one sure is a much bigger accomplishment .