How Long to Wait after Overseeding

before you can mow the lawn? Two weeks ago, I mowed lawn and did overseeding to repair the lawn areas damaged by the summer heat and drought. The seedlings (tall fescue) are a coming out but the old, existing grass is growing to about 5-6 inches now. I am afraid of damaging the seedlings if I cut the grass. As a general rule, when can I mow again? I can set the blades high so that they won't touch the seedlings.

I usually wait untill they are well established then i am very careful for about 2-3 mowings.

Cut but keep the blades high