Falls happen fast enough such that conscious thought will have no bearing and only instinct will prevail. You do develop instinct, however, through LOTS of 'fall' practice - unfortunately at our ages, that practice/instinct has already been deeply ingrained (or not) through the sports we participated in during our invincible/pliable youth. At 50+ we are not going to develop better fall instincts, rather, just hope the remaining instinct loss is slow.

If you grew up with judo, then perhaps you can instinctively tumble safely without using hands/arms, but I know my own instinct is to absolutely first use my hands/feet/limbs to break a fall before my head/torso touch the ground. Limbs have greatest range of travel and therefore are the body's best nature shock absorbers with which to decelerate an impact to head/torso, assuming your practice/instinct is not to stiff arm/leg it. Also hands/feet/limbs are completely expendable, while things in the head/torso are less so.

My own background is downhill skiing from 4 yo. - can't imagine better practice for falling at speed on a relatively soft surface. This led to numerous life-long speed sports like skateboarding, rollerblading, ice hockey, and street/dirt motorcycling, not to mention being a gymnast. I've fallen countless times on all sorts of surfaces, at all sorts of speeds, and from all sorts of heights, and plenty without protective gear or helmets. I've lost a lot of skin to road rash, but knock-on-wood, have never broken a bone or had a concussion.

The instinct to break falls with my hands is so strong that I first reach for gloves, for lower speed sports (eg, hockey, rollerblading, skateboarding), and then only add helmets as speeds increases (bicycling, motorcycling).

There's no right or wrong way to fall - you will just do what you are used to through instinct. If you are not used to falling.... then take less risk, or add more protective gear.