Good advice from Bike Nerd about trying stuff on. The “fit” of these things is all over the map.
We have a group of 10-12 riders that I’ve labeled Team AARP since most of us qualify for benefits. I’d say about half wear lightweight knee pads like the G-Forms https://g-form.com and only one guy (our oldest at nearly 66) wears elbow pads. I personally only wear pads on BIG feature rides or when riding in the bike parks in which case I’m also wearing a full face helmet as well. To be honest, while I’ve scraped up my knee 100’s of times over the years, I don’t crash often enough where I’m willing to sacrifice my comfort to climb all day in pads. I’d also cook wearing them in Austin as heat is my nemesis.
As far as elbow pads…good luck. I rode dirt bikes from age 6-48 and have been mountain biking since 1989 and I’ve yet to find elbow pads that stay up properly with all the shaking & jarring of riding dirt bikes and mountain bikes. The best ones were some Troy Lee options from my dirt bike years that covered my forearm and elbow together.