IMHO an instructor should have their student ready to deal with whatever the likely scenarios are at their aerodrome before allowing them to go off solo. I soloed at a large (albeit pretty quiet) international airport. Pre-solo I knew how to orbit when downwind and plan my spacing in relation to 737s coming in. At other places, if I heard that there was a 747 coming in I might get a bit distracted! Turned out I didn't need to - but I was prepared.
The OP has logged 60 hours (before soloing), presumably a fair amount of that where he soloed. I suspect that wasn't the first time that he (with an instructor on board) needed to switch runways, and his instructor would have been confident that he could do it. If his instructor wasn't, there would / should have been some quick phone calls to ATC! However - mistakes can be made by anybody - I've learnt something in his post which is good.
The link that Mad Dog posted of the AAIB report shows what can happen when a student is given something they don't have experience in dealing with. I'm definitely glad of the "student" tag on first contact with ATC here. Maybe it should be adopted everywhere else?