Can I Spray for Weeds?

I seeded for Centipede About a month and a half ago. Some areas of my lawn are being taken over by weeds and crabgrass. In the beginning I let them grow to prevent erosion, but now they are getting out of hand. Is it too early to spray for weeds, or use a weed and feed?

On a separate note, is it too early to mow?

Thanks for the help!

A picture of the good growth area.


A picture of the weed infestation.