You can drink it anytime you want. Normally, meads are higher alcohol like wine, and can be very "hot" and boozy tasting until it mellows with some time. If that doesn't bother you, then you can drink it anytime.
Normally, you wait for fermentation to be finished and for the mead to be clear before bottling so there is no sediment falling out before bottling. I don't want floaties or sediment in my bottles. That may take some time.
Once it's clear, and no longer dropping any lees at all after at least 60 days, then it's ok to bottle it.
If sediment and cloudiness aren't a concern and you don't mind that, then you don't have to wait.