I've found seateds, reales, and even gold coins that weren't deep. Heck, I could hear them on my pinpointer before I even started digging

It just depends on where you hunt. Only undisturbed turf seems to be stratified by age (the older, the generally deeper it is). But other locations don't have this: furroughed fields, old-town urban demolition sites, beaches after storm erosion, cow-pasture type terra firma, etc....
The trick to finding "anything cool", as a beginner, is to hook up with person(s) in your area, who routinely bring in the old stuff. Ie.: not just sand-box hunters, or big-talkers, but someone who actually comes in with the older stuff. Do you have a club in your area? If someone can even take you to a "gimmee" location, even if it's only '50s wheats/silver, then you'd "get the recipe" of what your machine is saying, by trading off flagged signals. See the type places they go, see how they swing, hear the type signals they are isolating, vs the ones they elect to pass, etc.....
If you have no one good in your area to shadow/watch, another option is to find areas with ample easies, to learn from simply digging 100's of targets (making mental note of sounds correlated to what you actually ended up digging, etc...). A good location for this type practice is yards of homes from the 1940s/50s. Yards this old are old enough to have silver, yet new enough to not have been hunted by others (as hardcore guys won't usually bother knocking on doors of houses this new), and new enough to be more unlikely that it is re-sodded, filled, junked out, etc.... Once you learn the sounds of easy common silver (roosies, mercs, etc...) from easy spots like this, THEN you can have a fighting chance in the hard worked parks, schools, etc....
And ultimately, you might want to upgrade from the Ace 250, if you did plan to work hard-worked parks and such. It's not a particularly deep seeker.