I'm a big advocate of defoliation, but with it being your first grow, you're better off not doing it. Reason being, they act as a buffer between a bad feed and losing your plants. You'll notice most deficiency/toxicity in the fan leaves first and the plant can use them as reserves.
If you're confident in your environment, root temps, room temps, pH, pests, etc, everything, then you can get rid of some. take the big fan leaves that are blocking light penetration.