What I would have told intermediate me is different. I wanted answers when I was a book devouring teenager, and I was too quick to think I knew things, case closed.
So I would tell myself to learn what I could but be aware others were doing the same and might demolish all those sensible looking answers by asking new questions.
The changes in how we do basic things over the 55 years I've had fish have been fantastic. The rules have changed.
I started with people around me chasing the no water change ever balanced aquarium, a myth that persists but isn't THE RULE anymore. We feed differently, stock differently, and in a lot of situations, see fish differently. There have been some very stupid fads over that period, but a lot of growth too.
I'd tell myself to keep accepting change but with a skeptical, practical eye. If something ain't broke, accept the idea that maybe it can still be done better. You are always a beginner in the hobby - aquarium experience is just having begun more things than you thought you ever would.