Promotion at Work

I found out the other day that my general manager wants to give me a promotion at work. This is exciting because there are certain advantages to being promoted to shift leader (basically a manager). One good advantage is that I get an increase in pay. Right now I make minimum wage which is $7.25 an hour. This is a really good minimum wage, considering just two years ago it used to be $5.50. Now that I am going to be in management, I will be getting paid $8.00 an hour! This doesn't seem like much of an increase, but considering its more of a raise than some people in regular professions only get raises of a few cents every year, I am pretty darn happy. This will help with my car insurance payments and my loan payments every month. Another advantage is only one other person has the power to tell me what to do. Now I don't have a problem with authority, but when someone is being rude about what needs to be done, I get a little agitated. I can now be firm but nice about what needs to be done, which makes me think that alot of people will respect me as a shift leader at work. One disadvantage of getting this promotion is that there is more responsibility. I will have to keep everything going smoothly, deal with customer complaints, and close the store. I've only had to deal with customer complaints at times, but other than that I am completely lost on what to do. Another disadvantage is that it will be weird telling people who are 40 years older than me how what to do. Of course I will respect them when I ask them to do something, but if I were in their position, I would be a bit jealous and mad. Other than these few things, it really is an honor that I would be even an option to be a manager at 19 years old. Hopefully I will do a good job!