tngecho, it seems you and I are in good company with "old timers" here, so I wouldn't worry about that.
In answer to your question, I blush to admit that I'm so old fashioned that I still use notebooks and paper to build my worlds.
As an example, my most detailed world started as a map on a 36"x36" hex sheet. I drew the map, thought about where geological features should be, what nations should be there, what wilderness/unclaimed areas should be there, the races I wanted, what were the relationship between all these groups. In the end I wound up with a world where there were two types of dwarves: mountain and hill. The mountain dwarves considered themselves the only "real" dwarves. They are a warrior people who dwell in citadels dug into the mountains of a central mountain range, split by a chain of volcanoes. They are a tough, disciplined, hard people who enjoy strong drink and battle between two honorable foes. For one to draw a weapon on you and proclaim he (or she) has decided to grant you the Gift of Battle(!) is a high honor. Both males and females are bearded and the braiding of the beard - with its knot work and decorations - tells you the clan, family, rank within both, occupation, and rank within that occupation of any dwarf.
I'll stop there, but you can tell that I've drawn on several archetypal sources for dwarves, but have added some twists and flairs. Some has even been added by players being told basically the above, and then working with me to fill in any blanks that might come up. In the end, I have a 2" ring binder filled with notes on the Dwarves of Kardin, the nations of Kershalt, Eufaula, The Thousand Realms, and more. There's the legends of the First Emperor and his Companions who defeated Orcus and broke his scepter in the Demon Wars.
Sadly, I think in various moves I may have lost that notebook, but the outline is still in my head.
Anyway, I really set out to write that you should never underestimate the power of just buying a map sheet or a notebook, and just start sketching out notes of things you think would be neat to have in your world. Then start connecting it all together and expanding further. Maybe run a game or two and see what your players do with this sketch-start you've made, though I do recommend more experienced players for doing that.
Hope this rambling bit was at least a little helpful.