lawn identification

Howdy,
Our house was built in the 1940's I'm assuming our lawn is about that old as well.  There seem to be many kinds of grass and more types of weeds on our 1/2 acre.  How do we figure out what kind of grass we have?  Does it really matter?  With a 'lawn' infested with a gazillion type of weeds, and not quite that much money, where do we start to acquire the coveted lush, soft, green lawn our daughter may one day be able to toddle across barefoot?

If it were me, I probably wouldn't care about grass varieties.  I would treat it as if it were tall fescue and the varieties that are closest to that will eventually win out.

If there were prickly weeds in the lawn, like thistle - I would pull those.  Not much fun when you wanna be barefoot.

Mow high.  Water infrequently.  Fertilize a bit.  Be patient.