Am I overreacting to my job promoting a coworker to manager?

I (m 23) work at a small retail store in a mall, we have 15 total employees 10 sales associates and now 5 managers. One of the sales associates who just turned 18 decided to ask for a manager position after just getting employee of the month for the first time after working with the company for 9 months. They were originally told no but just 3 days later I find out that they just got the promotion. I have also been with the company for 9 months and would have liked to be a manager one day but felt that I still might have needed more time. I have gotten employee of the month 3 times and now wonder if I could have asked for the position. I thought I should have waited things out after hearing that my coworker was initially denied the promotion. Am I overreacting to the situation and should just let it go?