Maybe try putting a little foil around the edges to keep them from burning until the middle finishes cooking?
It's too late to change the temperature of your oven, but I always bake my cakes at 350 F. Try tenting it with foil...that works for pies, I'm not sure about cakes.
At this point, you may need to start over to avoid an overly dry/uneven cake. 
good luck!
Next time try the wilton strips. You soak them in water then place around the cake pan helps keep the edges of the cake from burning and the middle of the cake to cook evenly eith the rest of the cake.
One time I felt my cake was overcooked on the edges. I just cut them off. The cake was smaller; but I used it for my family. I baked a new one for the customer.
I make 11x15 all the time, always 350 degrees. Always baking strips. Never a heating core such as a flower nail. They always come out perfect. I usually check them at 24 minutes and always bake at least five minutes longer.
just remember oven temperatures vary, you may want to get a thermometer to double check you oven temp. also i agree with a previous forum writter, use the wilton strips, they help alot!!! look for a coupon for michaels and maybe you can find them for 1/2 price.
i bake at a lower temp. it takes longer but bakes them more evenly. also, how are your rack placed in your oven?
try, try again... 
I have made a few of these and use at least 2 flower nails and that seems to help. I also bake at 350.
(as a suggestion - you might want to try typing in regular type, rather than all caps. it is hard to read and online comes across as "shouting").
also - sometimes helpful to see what works best for you - I bake my cakes at lower temps for longer times and have greater success that way (between 300 and 325)
I use the homemade cake release ( equal amounts Crisco, oil and flour) and have never had any burning on the edges and it has always released perfectly, cheaper too. I also use 2 to 3 flower nails in a cake that size and so far knock on wood it has worked for me. I am one of the ones that had nothing but problems with the wilton baking strips !
The flower nail acts as a heating core. It's good on big or deep cakes. Anything metal in the center of the cake draws some additional heat to the middle of the cake so it bakes from the center as well as the edges.
thank you for the flower nail reply, i will have to try this, i have some bigger cakes i will be baking today. so one will be enough for a 14'' pan?
I think so. If you do a search, you'll see many discussions about the use of the flower nail and people's experiences with what size pans to use them. Personally, I don't use them on sheetcakes; but I DO use them on deep cakes.
I make my own baking strips by measuring the height of the pan x 2, then the distance around the pan plus 2 to 3 inches. I then cut terry cloth (aka old towels) in these dimensions, fold in half and there you go...baking strips. I use t-pins to secure them around the pan.
I use t-pins to secure them around the pan.
Moonflowerpc, welcome to cake central! Enjoy it! I also make my own baking strips; but no more t-pins for me. Sometimes when I secured with pins, I'd pick up the pan to put it in the oven and a corner would slip off. I use binder clips now. One about an inch from each corner of the pan.
Thanks, the clips would be much easier to use!
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