If it was at "max ZFW" , ie maximum Zero Fuel Weight, it would not have been able to have a full fuel load as well. Max ZFW + max fuel would exceed max take-off weight.
Also, after engine-start, taxi, take-off and climb to 3000ft quite a bit of fuel would have already been burnt off.
Finally, just to be (even more) pedantic, as it is an Airbus the term is ZFM ie Zero Fuel MASS. Kgs are units of mass, not weight. Airbus use the correct term in their FCOM, unlike Boeing who erronously (along with 99.99999% of the popultion) use "weight". The unit of weight is the Newton ie mass x gravity.