ATL is huge and you will most likely have to take a tram to switch terminals. As long as your flight lands on time, you should be ok. But if you are delayed, it can be dicey. I fly delta a lot, and have more than once had to actually run to make a connection in ATL that should have been "enough" time.
I hate when they "help me out" by tightening my connection time. It may be worth looking online to see when the next flight runs. Even if you opt not to call and ask to be switched, it always makes me calmer to know that if I do miss a connection, there is another flight they can put me on. Often, though, I call and point out that this is not my choice, and if there is another flight they will switch me at no charge. YMMV
And pasodancer is right, you want to be as close to the door as possible. You can lose a ton of time waiting on people who do not have tight connections to deplane.