I suppose I'll put up my two cents. I actually started in fast food and the environment is still the same, nasty customers, nice ones...etc etc.
bottom line here is:
management experience is a plus and it will definitely change some of your perspectives on business and your role in the work force
I think it is an opportunity you should take
HOWEVER
managing a wendys (or any fast food) is difficult and requires a lot of work (as do a lot of management positions)
when you look in the paper and a lot of places are asking for management there is a reason for it. I believe, to be an effective manager one must first possess the right attitude for it...(I.E. not a pushover, assertive, demanding, semi compassionate..)
A lot of the times it's a conflicting role you must play and it requires being a manipulative person and sometimes a ruthless person.
If you're too demanding people won't like you and you'll piss them off..then they'll all quit and not stick around.
If you're too nice they'll take advantage of you, your food, call out, horse around.
So you have to be good with people, reading them and being able to get what YOU want out of them.
The other problems with MOST fast food, if not all now, is that they are franchised operations..which means..you are super micro manager because you have to please your franchiser. Franchisers can be very pleasant and knowledgeable OR they can be big piles of steaming horse crap and moronic, annoying and ridiculous.
you're most likely going to have the latter.
IMHO, they are actually far worse than just being corporate because it's another person above you that is more than likely going to be around ALL THE TIME that you're probably going to pretend to like and curse behind their back.
You will be promised things you won't get, such as bonuses or other incentives, you will most likely not be helped when you need it the most and although your input may be heard and proclaimed as valuable for things such as LSM (local sales marketing) and staffing, product value and quality ETC...
it will most likely fall on deaf ears.
The reason I'm using words such as most likely, probably won't and the like is because it is possible to work for an awesome franchiser but I'm giving you the norm and the attitude of the majority of them.
Being a manager you will be in charge of a lot of workplace ethics, among them being hiring, firing, and dealing with unhappy customers and stuff like that. You'll be expected to make and break sales records from the previous years EVERY week. So you get a lot of stress and pressure just like cooking but in a different form.
I also want to add here that you will get a lot of older worker bee's angry with you for petty things such as the mere fact you replaced the old manager or the fact that you are so young and managing them...somebody in their 40's. They will take their angst of being older working in fast food out on you because you're so much younger.
It's not right and ridiculous much of the time but it will happen. Fast food environments are barely work environments meaning that although they work hard too there is limitless clowning around and not much structure. I believe part of the reason for this is because the turnover is so much higher than the applicant pool of which you can draw from.
If you plan on having a family don't plan on being a manger and I'm about to share with you the worst part of managing.
You may take home 500-600 (more once you have experience) a week but that's pay for only 40 hours.
Expect to work around 50 or 55 and don't be surprised if your weeks are about 60 or 70 a lot of the times. The key to working less is hiring the most reliable, competent people you can find and then keeping them. This is a huge problem though because the pool of people that apply for fast food places isn't what you would call...stellar. You're gonna get a lot of kids, a lot of part-timers, A LOT of people who can't handle anything else let alone the job you want them to do...
If you overwork them they get upset (rightly so), if you underwork them they get upset
everything is balance as a manager
If you do get a really good employee or too chances are they either want your job or they are going to college soon or don't plan on staying forever, the harder and the more you work them the quicker they'll bolt out the door (and rightly so)
So, like I had previously stated
I believe you should take the position. It will really do you a lot of good. It's shows responsibility...yadda yadda..all that.
I believe somebody already posted it but don't ever go into anything like you plan on keeping it forever. Plan on doing the best job you can and learning as much as you can until you find something else.
Because there is always something better..
I mean, maybe someday you'll franchise
good luck!
Possible Job change, same industry 
