A question about a scenario.

Hello,
I have a question about a scenario and I'm thankful if anyone share their opinions about it.
A website, provide selling and buying the stocks. The normal algorithm for selling and buying must be FIFO(First In First Out). In the website, you select the stock, its numbers and..., Finally, you click on the buying button to order the stock, but lees than a second, thousands of people are in the queue? How?
I used a script to click on the buying button in 2 millisecond, but I was 2XXXX in the queue!!!! How the people send their orders earlier than me? Any tricks?
Is it possible to manipulate the request that sending from my computer to the server?

I'm thankful if anyone share any idea.

Thank you.

I used a script to click on the buying button in 2 millisecond, but I was 2XXXX in the queue!!!! How the people send their orders earlier than me?

Do the math.

There's "one" of you, competing against "thousands" of others.

The website blocking you if you sending a lot of requests in a second.