The actual age for nodal return is 37 years and two months. And that's the second one. The first is at 18 years 7 months. If you were 38 when this transformation happened for you, it was about a year past your second node return. Whatever transits were happening in that year, when you were 38, would be more pertinent.
I have observed a running theme in my node returns (I've had two), but it's a minor note. Each time, something happened that reflected the theme of my north node placement. For me, that's Scorpio, eleventh house.
Both happenings were people coming into my life. At my first node return, when I was 18, it was a person with some very dark secrets. I'd known this person casually for a couple of months, but on the day of my node return we had our first significant interaction, and it was a huge conflict. It ended with me telling them off, very forcefully. Turned out, this person has the utmost respect for people who dare to tell them off... so that started us being friends.
The reveal of the secrets came a couple of months after that. That was in the eclipse season closest to my node return. Incidentally, Pluto was sitting on my north node during that return--perhaps that's why the experience I had then was so heavily Plutonian.
When my second node return was coming along, I decided to try hypnotherapy... not just because I thought it would be fun, but because there was some serious nasty stuff going on that I couldn't work through, and a conversation I overheard made me think hey, maybe that would help. Then a hypnotherapist turned up in my network. We emailed back and forth a few times, scheduled an appointment... and when the day of that first appointment came, my node return was exact. (Scorpio, remember, is the sign of the hypnotist.)
That did end up being a deeply transformative experience, but I'd say the node return itself was a minor note in the big picture.