I know very little about criterions, but if you have never raced before, you should, as Alison suggests, join a few packs. Each race type has specific protocols, as well as more general protocols. Crits are very fast paced - be prepared

If there are no time trials organised, no worries.
A TT is a race against yourself - so go out there over a measured course and try it... then keep riding over the next week or so, and then TT again and if the weather conditions are similar, you'll maybe do a better time.
Just set yourself goals and meet those. The 2-3 months will pass quickly
Best wishes for the training