There should be no problems with that weight.
I am 29 and 100kg and had no undue side affects when teaching in the C152 (and we had the heaviest C152 in NZ!).
The C152 with 2 standard people and full tanks is over MAUW anyway so you just have to take into account the fuel required for the lesson.
It actually helped with x-country training. It made the stud. think about what fuel we could carry and how far we would get with that fuel.
S2K