That Moment When...

Hey there! How are you, today? Purple here to give you a review! Let's get started
I rather like how you connect the first line of the poem as the title, it has a certain uniqueness about it. Just a few things I would suggest to edit.
"I start, I shake in my seat." The line "I start," isn't very strong on it's own. How about :"I start to shake. Alone in my seat" or something along the lines of that where "I start" wouldn't be on its own.
"My classmates look worried-" The hyphen is not needed in this line. I would suggest a comma instead.
I hope this was helpful. Have a great day and keep up the good work!
~Purple

Hey Weather here with a review!

Well I really liked the story you're telling here and the slightly dramatic element to it. It was also descriptive so the reader can go through the same motions as the character. The rhyme schemed flowed pretty well together.

There is however, always room for improvement. There were a few things which interrupted your flow. Also some punctuation errors.

"I panic,
I start,
I shake in my seat.
I am quite overcome by a sense of defeat."

Here your second line, "I start," it didn't really make sense, I suggest you remove it as it's quite unnecessary, or you could link it with your third line so they flow together a bit more. Or you could just simply describe something else you begin to feel. Your fourth line is a little long and it isn't very grammatical and contradicts what your previous statements were. Your beginning statements were direct and stated what was happening with the character but the fourth line suggests that the character isn't in a very bad state as they're just "quite overcome" It's a bit more relaxed which doesn't fit. "I am overcome by defeat" would be more fitting or something along those lines.

"My classmates look worried-
I've turned white as a ghost.
They can't see that I've lost
What I love the most."

Here, the hyphen isn't necessary perhaps a semi colon. The second line, "as white as a ghost" isn't the most interesting description maybe as: pale, lifeless, colorless...etc something like that.

"I try not to scream,
I try not to shout,
But I can't believe my biro
Has gone and run out."

*biro should be capitalized but it's fine in lowercase too. This was my favorite stanza., the last line made me chuckle.

Overall a nice piece keep writing! Hope I helped.

--Weather