I have about couple of dozens also planted in fall. The tops are huge and stems are healthty.
I have noticed just one with bud. I will let it go to seed
so I can collect seeds.
But budding, does not mean that you should pull them up, as you have
already checked, that they are not ready and perhaps will
not be till the end of May.
What you can do is to pinch off the flower buds.
Shallots are similar to onions planted from small pearl onions. The diffrence is that onion will grow just one, but shallots can grow 2, 4, 4, 5 ... in a clump.

Thanks, cyrus_gardner. That's exactly what I needed to know! Commencing bud pinching. ;)

The buds are probably edible too. ;)