Better harvesting a bit too early than a bit too late. You may lose a bit in final bulb size, but too much delay results in bulbs that fall apart and do not keep as well.

I am near you, north of Bellingham. Some of mine are starting to fall over as well. I planted the variety Italian Silverskin, I think. It's the variety Joe's Gardens sells as braids in the fall. I haven't dug any yet, trying to give it as much time as I can, watching for the bottom five leaves to be dry.

Could be leek moth larvae (from Europe, I think - acrolepiopsis assectella - different from allium leaf miner which is a fly larvae)...along with the white rot on the plot, alliums are just a memory for me now. Astonishingly, I can manage to grow non bulbing spring onions and a decent crop of leeks as long as I use a specific resistant F1 variety - 'Oarsman'.

If you only have a small number of plants (as shown in the photo) it is probably not worth the gain-vs-loss to harvest the plants young. They would basically be garlic-flavored scallions... and if you might want such early Spring "garlic", I would recommend Chinese chives. Those have the advantage of being perennial, spread to form large clumps, and can be harvested from late Spring onward. Walking onions are also perennial, and are both the first & last veggies I harvest each year.