Round here, the snowdrops and catkins come out typically a week or two before the calendar date for Imbolc. So, if you go with the date, these seasonal markers aren’t the ones to focus on. If there are pregnant or lactating sheep in area, I don’t get to see them.
What does appear reliably at this time of year, are elf caps. These are a small, red fungi (see the video below for examples!). They have a much longer season over all, but where I live, they are absolutely something that shows up for the start of February.
The relationship between what the rest of nature is doing, and the calendar date varies according to where you live. Druidry can be a bit generic about seasonal celebration, which I think is a real weakness. We need to dig in with whatever we’ve got where we live, and make that the focus, or shift our dates so they match what the season means to us.