jana1, a brand new oven can be where the temp is not even..."hot spots" in front, back, or one side or the other or that the whole oven temps can be off from the dial setting. There are adjustments screws on the bottom of most oven dials for this reason (underneath when you pull the dial off)...not a real common known fact to most homemakers. That is why one or more oven thermometers (they hang on oven rack) is a real good thing to have if you want to do a lot of baking. That way you know for sure what your oven temp(s) are. A oven that is off is a real "headache" when baking breads, cookies, pies, cakes and the like...not quite as bad with casseroles, roasts, pizzas...they can slip by without you really noticing something isn't just right with the oven.
Another tip...with any quick bread...muffin, biscuit for example...do not over mix or over bake. Mix/stir by hand not electric mixer...you will have some lumps...but that's ok...no lumps=tough & rubbery.
Try checking a few minutes before the "called for" baking time...It is done when a toothpick, inserted in the center, comes out with just a few moist crumbs. (You can also try the "smell 'em - check 'em" way...I guess I'm guilty of doing it that way mainly myself on most baking...but for starters you probably want to use the timer

)
When done...immediately remove them from oven and place the pan on a wire cake rack to cool slightly...take from the pan and cool on a wire cake rack (if they sit in the pan they sweat and the bottoms become soggy.)
Hope this helps some.
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~to those who can dream...there is no such place as faraway~
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