DS is 17 months and SO obsessive about everything being in it's right place/doing things in the right order and so on. For instance, we were in a bakery with him in his buggy this morning and the kind lady serving handed him a free mini chocolate pastry (his favourite sort). He took it enthusiastically but refused to start eating it until I had got his bib out of his bag and put it on. He insists on so many things: wiping down his high chair once he's finished eating (he'll do this himself if you give him a cloth!), putting his dirty nappy in the bin immediately, taking his shoes off as soon as we get home and putting them in the same place etc, washing fruit before eating it (he often reminds me to do this). Yesterday morning I was about to leave the house with him and he reminded me that I needed my keys! Both DH and I are fairly tidy and organised but only very ordinarily so. He seems to have a very good memory for processes/routines and will ask or initiate repeating activities even after we've only done them once - for instance, I showed him how to put soap on his hands and wash himself in the bath one evening and he has initiated this and insisted on it in every bath since. Needless to say he throws a tantrum if he is thwarted in any of these routines.
It would be great if you could reassure me that all this is normal at this age! His personality seems very cautious/careful but otherwise we have no concerns.