You just answered that question from your own experience! That's the truly valid answer.
It does. And then some. No lifetime, even a long one, even if you start young, is enough to understand it all.
There's more than one kind of progression. Secondary progression is the most commonly used kind today, so "progressions" has become shorthand for secondary progressions. If someone says, "my progressed Venus..." without specifying what kind of progression they mean, it's a safe assumption that they mean secondary.
The only other kind of progression that's used fairly commonly is solar arc. Generally, when people talk about solar arc progression, they specify solar arc, or SA.
Other kinds of progressions exist besides those two, but they're pretty much obsolete.
Horary goes over everyone's head, when they're new to astrology. It's extremely complex, and it has a high learning curve.
Before you learn anything else, you need a good working knowledge of signs, houses, planets, and aspects. All astrology is built on that. How well would you say you understand those?