I want to translate "I thought I knew something, then I realised I knew nothing" into Latin. The result I got from Google translate is this "Quod cogitavi cognovi: tunc animadvertebam nihil scirem." I am completely Latin illiterate and I would like to use this sentence as a motto for an event. Please help.
Putavi me scire aliquid, tum agnovi me nihil scire.
Starting the main clause with "putavi" emphasizes the fact that this thought is now far from us; also, ending it with "aliquid" gives more importance to the fact that it's not nothing.
In the secondary clause I used tum, as in, following that - if your "then" is more like "but then", this may be substituted by autem.