I would suggest checking the box of whatever the chosen set turns out to be.
Make sure it says DCC ready or DCC fitted on the box when describing the locomotive, if it doesn't specificaly have one or the other don't get the set.
DCC Ready, indicates the locomotive can easily be fitted later with a digital chip to turn it into a DCC locomotive.
DCC Fitted, indicates the chip is already fitted.
In each case it will have the right basic train controler in the box.
NOTE as the layout expands it will be nessasary to buy a better controller, unfortunately the controlers that come in sets cannot handle much more than is in the set this is common to all manufactures of train sets.
I would also recomend a trip to a good bookshop or hobby shop and getting a good beginers guide to model railways and a good beginers guide to wiring a model railway as well.
Don't go in too deep too fast (this mistake must be avoided) but do set aside a place where it can be set up permanently on a properly made set of bench work for the railway.
This is only the first layout "mistakes" will be made accept them learn and progress and it won't be the last layout built, each will be better than the last one as you learn and decide what you really want to do.
The most important thing is to have fun thats what the hobby is really about
We can all bore you to death with the rights and wrongs later and every one has a different idea as to what those are.