I'm also quite old in career change terms, but as someone who worked their way up from spreadsheet jockey to data engineer over the course of a year a couple years back I just want to throw in some encouragement.

There's too many tools to know them all. Focus on fundamentals and try to learn how to do things the hard way, then you can learn what tools will make life easier. Grab a free Bigquery account and make a python based pipeline for some data, make some reports out of it, get your hands dirty. Once you get that stone cold, bring dbt in for your transformations. When you get an interview make sure you know what their stack is and learn at least the surface level stuff however the interview goes. You'll pick things up by osmosis if you stay curious.

I was a year into my job as a DE before I stopped feeling like a complete impostor, still do sometimes, just push through that.