Personal opinion, get that third level of farming before anything else. It may hold off your puzzle solving a little longer but once you have that, you'll never worry about food. You can start growing your population and once you have more villagers, everything goes much, much faster (more people to work!).

However, if your villagers are starting to get "old", you may need to grab that level 2 of medicine to hold on to your workers a little longer.