43 ain’t old if you’re in reasonable shape. I say go for it. Don’t be stupid about it, get pads, wear a helmet, start slow, get a coach. Otherwise, you’re checking into the old fogey hotel and every year you don’t keep active is a year closer to the grave. And I’m two decades older than your relative!
IMHO, it’s different if she did a little roller skating or whatever when younger. If it was zero, then I’d be kinda leery. If it was a beginner even intermediate level, what the hell, just take it slow. If she was good when younger, the greatest danger is thinking she can still do what should could do back then, and prolly not.
Personal example 1: I was a barely beyond beginner snowboarder (ok skateboarder but had never skiied). went snow boarding a half dozen times in University, went snowboarding a half dozen times 10 years later in Japan, then i went 20 years after that near Seattle. Never had a lesson (except for a couple of chairlift folks that volunteer to show me a few things). I was 5 years out of shape when I restarted at around 52 years old as my youngest kids started skiing. 2nd time I went, I pulled a stomach muscle. But I came back from that, it forced me to get into reasonable shape, and for about the last 10 years, I hit the slopes 30-40 times per season. BUT, I was never good back in the day, so I never have tried to relive my youth and do one “last run” ripping through the trees blindfolded with one arm tied behind my back. This is how a lot of people later in life get injured: retrying what they could do 40 years ago, hadn’t attempted in at least a decade, and thinking they could still do the 360 flips of youth.
Personal example 2: I did 4 years of Kenpo karate pretty seriously from 1978-1982. Second degree brown belt, knew 6 katas, fought in open tournaments and usually advanced a few rounds, taught the beginner class. In other words, I was pretty good. Didn’t do anything and started taking private lessons 40 years later. No where near the same level, but I have relearned 5 of the kata’s and #6 will be done soon. Not sure if I want to join an actual class and start sparring again. Relearning the kata’s and working on all the basics to get back to an okay level first.
Personal example 3: I still backpack. Ok, I don’t carry 45 pound pack for a month solo in Tibet any more. In fact got my first ultralight backpack two weeks ago, and pack out weight without food, beer or water is 10 pounds. But the day I won’t go a few miles on a trail to a mountain lake in nice weather to hang out, make dinner, read kindle, drink a 6 pack (starting in the parking lot), sleep in a tent on a yoga mat, and enjoy the experience, is the day I let everyone in the world know I’m officially old and readying plan B to pull the plug when I can still make the decision.
Plus age. Arthritis creeps in, feet get wider, not as flexible, not as fast, coordination drops, maybe a beer belly, etc. Don’t be stupid about activities that might cripple you for life, but holy moly, 42 ain’t old. And if not now, when?