This is a difficult question. You are never guaranteed to have only positive experiences with psychedelics, and not to have any anxious feelings.
The combination of ketamine and shrooms is physically safe. That much i can say.
My experience with anxiety is that the more you give in to it, the more powerfull it becomes. So in that sense, waiting and postponing, is making you weaker everyday. For that reason it would be a good thing to no longer wait and just do it. But it is easier to take that step, if you contemplate it and ask yourself whether this is something you realy want or not. If you have established for yourself that you realy want to do it, then there is no reasen to wait for another two years.
On the other hand it is completely OK to say to yourself that you don't want to take the risk. But i think that keeping yourself in a sort of limbo about this, for another two years will probably not do you much good.