When should I rack my mead?

I'd let it keep going until you see that some sediment has accumulated on the bottom of the carboy. The purpose of racking is to remove the wine or mead from the lees (sediment) so if there is little to none then you're not going to gain much of anything by racking.

3-6 weeks is the usual time to do the first rack of a mead, but it's best to check with a gravity measurement first. Gravity should be around 1/3 the starting gravity, and some of the yeast should have flocculated on the bottom of the fermentor.

If you didn't add any yeast nutrients to the mead, then fermentation will go slower as the yeast have a harder time propagating up to the numbers required. Also, 60F is on the cold side, for some mead yeast strains, which will also slow things down.

Seeing you don't have any sediment yet, I'd wait a couple of weeks before racking, especially since it's fermenting quite cold. The amount of krausen with mead can vary dramatically from next to nothing to overflowing, even with the same yeast strain, so don't worry that there is no "head". But before racking, check with a gravity reading first.

Since this is your first brew, over the next couple of weeks, try to take time to search and read up online about the processes around mead making. Topics like, good racking procedures (avoid oyxgen), when to do the second transfer, when to add sodium metabisulfite or ascorbic acid, when to bottle and how long to age for. This will give you a feeling for what is typical practice, and you'll feel a lot more confident with the rest of the brew!