There are several places to ride local.
Ridgeline in Eugene is beginner friendly but heard the mtb section is currently closed for trail work. Check the map for open to mtb trails
Thurston Hills in Springfield has a nice green line Acer Spades. There is a group that rides there on Tuesday nites, Show up after 5 leave the parking lot at 5;30, (FB page- Eugene Mountain Bike Group). They will ride some trails wirh rocky tread (YewHaw)
Carpenter Bypass near Lorane is a network of trails, many are beginner friendly. I plan to ride there today, noon at North parking lot (gravel pile), I drive a green Tacoma and you are welcome to join me. Forum back if you plan to show.
Regarding riding fast , getting technical, and not falling, good luck with that. You’re new to mtb, learn to ride first, fall a few times, gain confidence then speed and tech…then fall some more.