my TDEE is different from MFP

MFP's calculation is NOT TDEE, unless you do no exercise.

That's why their selection of activity levels has no comments about exercise - exercise doesn't count until actually done and logged.

Then your TDEE goes up, then the same deficit is taken, then your eating goal goes up.

Also, MFP takes deficit as block of calories, 250, 500, 750, 1000 - depending on your choice.

TDEE deficit method usually takes % off.

So if you don't exercise, usually similar goals if the deficit is the same.

If you do exercise, usually similar if you add up a week of MFP and average it out daily, which is what the TDEE method is doing.

lost and getting a headache! JK! I don't know what these all mean...I guess I will catch on eventually.

MFP said my daily calories burned is 3,000, TDEE its 2275

You are likely confusing Diet goals with Fitness goals - there is no math between the 2.

And it's confusing because MFP puts them together during setup like they are.

Again, leave TDEE out of any numbers MFP gives you, because they don't use TDEE, unless you happen to do no exercise.
Otherwise it just confuses things.

Where does MFP say your daily calories burned is 3000?
Is that after you logged a workout? Then you could consider that your TDEE for that day.

Where does it say 2275?
Is that what MFP calls maintenance?
That's your BMR x a non-exercise activity factor based on your choice (Sedentary is 1.25).

There are also Fitness goals, where you can put in goal minutes, sessions, and calories. No bearing on Diet goals.

OP:
Read this link and all of the links in it. It will take you awhile to get through all of it, but it is worth it.

http://www.myfitnesspal.com/topics/show/1080242-a-guide-to-get-you-started-on-your-path-to-sexypants?page=1#posts-16625920