I'm not a student, but I have landed a couple of times on 04 and it does have a marked downslope - it's also grass which increases the landing roll, although I don't recall it being overly rough ground.
This is nothing to worry about for someone with experience, but more challenging than 1500m of level tarmac which is what I did my first solo on.
At the end of the day, a CFI will make a judgement call based on a pragmatic view - you may not realise, but you do your solo flying as a student on your instructors licence so if anything went wrong his/her livelihood could be affected, as well as your confidence.
I would n't be unduly perturbed about this experience, it demonstrates a safety oriented approach which is a good thing.