Hello Mark & Welcome!!!
Good to hear that you’re building a solid foundation! Follow Justin’s methodology & you can’t go wrong!
As for Dm… as with any chord, it’s going to get easier the more you play it! There’s no substitute for short frequent sessions! You got that one right!!!
Fun is another key ingredient… when you’re smiling & happy whenever you pick up the guitar, you’ll never give up, even in the valleys & plateaus of your Journey!
As for your photography, I haven’t had time to check out your link, but we have a thread here in the Community…
that has some astronomy themed photos you might enjoy. Lots of other fun pics in there too!
I’m wishing you much joy & success with guitar!!!
Good luck!
Tod from New Mexico USA