It's a sad state of affairs if the exchange needs to be "please share your situation with me so I can know if it's appropriate to offer words of encouragement" before offering words of encouragement.
Lets take an example of the most brilliant people of our time while also extremely handicapt Steven Hawkins.
What would he care he was excluded in a statement like this?
But it isn't really. Even taking that statement at face value you're still talking about people who are selected for their physical skills and then spend much of their prime training and preparing physically like their lives depended on it. Because it does. But they suck at many other things and they do have an excuse to not be able to do them.
One person cannot "specialize" in too many things and downhill extreme mountain biking is not a thing to do half-assed without risking your well-being. Getting the skill and the physical strength to do it is both time consuming but more importantly very risky.
I doubt you’ll hit 75kph with a 36V Motor though. My 52V mid drive would get me to around 40–50kph on a good day, flat terrain, no wind, and pedaling hard. I put it back to 25kph max because riding so fast on a bicycle was too dangerous in my opinion... cars don’t expect you to come so fast, and I was getting too dangerously confident. I was also worried about the consequences should I get in a crash and the bike is investigated to see whether it was legal.
For those interested in diy, the tsdz2 mid drive is a pretty good motor that has a torque sensor and that you can add to most bicycles. There is also an open source alternative firmware for it that’s pretty good. See https://github.com/OpenSource-EBike-firmware/TSDZ2_wiki/wiki
You don't need to be a great mountain biker to go dangerously fast, it's very easy to become overconfident, and the downhill nature means that you might also fall from certain heights on top of already carrying speed, and not necessarily on soft dirt, maybe onto rocks or into a tree. It's a gnarly sport.
The commentator you were talking to should at least go on some mellow bike rides or something.
BUD/S has like a 25% pass rate, of people who are even allowed to try.
Not saying that a navy seal can't just decide to not be tired anymore, but for the rest of us mere mortals....
It helps.
No critique. When you have to operate under circumstances like that and your life and your fellow soldiers lives are at stake it makes sense.
Has inherent problems though.
https://sofrep.com/news/navy-seals-get-addicted-drugs-doc-is...
... in the field. Same with pilots -- they issue speed to dudes flying bombers long distances.
But they're not taking speed during selection and training. That's just you, and figuring out if you can hack it is the point.
If mountain biking is your dream buy a Trek with electric motor in it. They can give you extra lift till you accelerate to 75 km/hour with a dongle of $120. Instant pro biking experience without much practicing.
You are too young to accept any physical limitations of your body. Navy Seals talk about that being tired is just an emotion like feeling happy. Its all about your mindset.